fix os.listdir return name is empty string

fix #6588

xlistdir return name is empty string

for example：
`
from datasets.download.streaming_download_manager import xjoin
from datasets.download.streaming_download_manager import xlistdir
config = DownloadConfig(storage_options=options)
manger = StreamingDownloadManager("ILSVRC2012",download_config=config)
input_path = "lakefs://datalab/main/imagenet/ILSVRC2012.zip"


download_files = manger.download_and_extract(input_path)

current_dir = xjoin(download_files,"ILSVRC2012/Images/ILSVRC2012_img_train")
folder_list = xlistdir(current_dir)

`


The docs for this PR live [here](https://moon-ci-docs.huggingface.co/docs/datasets/pr_6581). All of your documentation changes will be reflected on that endpoint. The docs are available until 30 days after the last update.


Obj ["name"] ends with "/"

@lhoestq 

hello,
Can you help me check if there are any issues with this PR? Why hasn't anyone merged?


<details>
<summary>Show benchmarks</summary>

PyArrow==8.0.0

<details>
<summary>Show updated benchmarks!</summary>

### Benchmark: benchmark_array_xd.json

| metric | read_batch_formatted_as_numpy after write_array2d | read_batch_formatted_as_numpy after write_flattened_sequence | read_batch_formatted_as_numpy after write_nested_sequence | read_batch_unformated after write_array2d | read_batch_unformated after write_flattened_sequence | read_batch_unformated after write_nested_sequence | read_col_formatted_as_numpy after write_array2d | read_col_formatted_as_numpy after write_flattened_sequence | read_col_formatted_as_numpy after write_nested_sequence | read_col_unformated after write_array2d | read_col_unformated after write_flattened_sequence | read_col_unformated after write_nested_sequence | read_formatted_as_numpy after write_array2d | read_formatted_as_numpy after write_flattened_sequence | read_formatted_as_numpy after write_nested_sequence | read_unformated after write_array2d | read_unformated after write_flattened_sequence | read_unformated after write_nested_sequence | write_array2d | write_flattened_sequence | write_nested_sequence |
|--------|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| new / old (diff) | 0.004968 / 0.011353 (-0.006385) | 0.003516 / 0.011008 (-0.007492) | 0.063787 / 0.038508 (0.025279) | 0.031695 / 0.023109 (0.008586) | 0.240081 / 0.275898 (-0.035817) | 0.260984 / 0.323480 (-0.062496) | 0.003832 / 0.007986 (-0.004153) | 0.002680 / 0.004328 (-0.001648) | 0.049199 / 0.004250 (0.044948) | 0.044720 / 0.037052 (0.007668) | 0.255812 / 0.258489 (-0.002677) | 0.275923 / 0.293841 (-0.017918) | 0.026849 / 0.128546 (-0.101697) | 0.010473 / 0.075646 (-0.065174) | 0.209069 / 0.419271 (-0.210202) | 0.035731 / 0.043533 (-0.007802) | 0.246596 / 0.255139 (-0.008543) | 0.265889 / 0.283200 (-0.017311) | 0.017607 / 0.141683 (-0.124075) | 1.128648 / 1.452155 (-0.323507) | 1.174379 / 1.492716 (-0.318338) |

### Benchmark: benchmark_getitem\_100B.json

| metric | get_batch_of\_1024\_random_rows | get_batch_of\_1024\_rows | get_first_row | get_last_row |
|--------|---|---|---|---|
| new / old (diff) | 0.098214 / 0.018006 (0.080207) | 0.311969 / 0.000490 (0.311480) | 0.000266 / 0.000200 (0.000066) | 0.000056 / 0.000054 (0.000002) |

### Benchmark: benchmark_indices_mapping.json

| metric | select | shard | shuffle | sort | train_test_split |
|--------|---|---|---|---|---|
| new / old (diff) | 0.018401 / 0.037411 (-0.019010) | 0.061347 / 0.014526 (0.046821) | 0.073628 / 0.176557 (-0.102928) | 0.121359 / 0.737135 (-0.615776) | 0.075148 / 0.296338 (-0.221190) |

### Benchmark: benchmark_iterating.json

| metric | read 5000 | read 50000 | read_batch 50000 10 | read_batch 50000 100 | read_batch 50000 1000 | read_formatted numpy 5000 | read_formatted pandas 5000 | read_formatted tensorflow 5000 | read_formatted torch 5000 | read_formatted_batch numpy 5000 10 | read_formatted_batch numpy 5000 1000 | shuffled read 5000 | shuffled read 50000 | shuffled read_batch 50000 10 | shuffled read_batch 50000 100 | shuffled read_batch 50000 1000 | shuffled read_formatted numpy 5000 | shuffled read_formatted_batch numpy 5000 10 | shuffled read_formatted_batch numpy 5000 1000 |
|--------|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| new / old (diff) | 0.274098 / 0.215209 (0.058889) | 2.707633 / 2.077655 (0.629978) | 1.453615 / 1.504120 (-0.050504) | 1.311942 / 1.541195 (-0.229253) | 1.332394 / 1.468490 (-0.136096) | 0.566947 / 4.584777 (-4.017830) | 2.383291 / 3.745712 (-1.362421) | 2.754779 / 5.269862 (-2.515083) | 1.725164 / 4.565676 (-2.840512) | 0.062124 / 0.424275 (-0.362152) | 0.005111 / 0.007607 (-0.002496) | 0.334217 / 0.226044 (0.108173) | 3.271619 / 2.268929 (1.002690) | 1.776906 / 55.444624 (-53.667718) | 1.519238 / 6.876477 (-5.357239) | 1.534722 / 2.142072 (-0.607351) | 0.646143 / 4.805227 (-4.159084) | 0.117015 / 6.500664 (-6.383649) | 0.042578 / 0.075469 (-0.032891) |

### Benchmark: benchmark_map_filter.json

| metric | filter | map fast-tokenizer batched | map identity | map identity batched | map no-op batched | map no-op batched numpy | map no-op batched pandas | map no-op batched pytorch | map no-op batched tensorflow |
|--------|---|---|---|---|---|---|---|---|---|
| new / old (diff) | 0.948488 / 1.841788 (-0.893299) | 11.598027 / 8.074308 (3.523719) | 10.269199 / 10.191392 (0.077807) | 0.144887 / 0.680424 (-0.535537) | 0.014745 / 0.534201 (-0.519456) | 0.289185 / 0.579283 (-0.290099) | 0.275243 / 0.434364 (-0.159120) | 0.328088 / 0.540337 (-0.212250) | 0.430161 / 1.386936 (-0.956775) |

</details>
PyArrow==latest

<details>
<summary>Show updated benchmarks!</summary>

### Benchmark: benchmark_array_xd.json

| metric | read_batch_formatted_as_numpy after write_array2d | read_batch_formatted_as_numpy after write_flattened_sequence | read_batch_formatted_as_numpy after write_nested_sequence | read_batch_unformated after write_array2d | read_batch_unformated after write_flattened_sequence | read_batch_unformated after write_nested_sequence | read_col_formatted_as_numpy after write_array2d | read_col_formatted_as_numpy after write_flattened_sequence | read_col_formatted_as_numpy after write_nested_sequence | read_col_unformated after write_array2d | read_col_unformated after write_flattened_sequence | read_col_unformated after write_nested_sequence | read_formatted_as_numpy after write_array2d | read_formatted_as_numpy after write_flattened_sequence | read_formatted_as_numpy after write_nested_sequence | read_unformated after write_array2d | read_unformated after write_flattened_sequence | read_unformated after write_nested_sequence | write_array2d | write_flattened_sequence | write_nested_sequence |
|--------|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| new / old (diff) | 0.005020 / 0.011353 (-0.006333) | 0.003246 / 0.011008 (-0.007762) | 0.049810 / 0.038508 (0.011302) | 0.032215 / 0.023109 (0.009105) | 0.271033 / 0.275898 (-0.004866) | 0.294957 / 0.323480 (-0.028523) | 0.004192 / 0.007986 (-0.003793) | 0.002652 / 0.004328 (-0.001677) | 0.049132 / 0.004250 (0.044881) | 0.047818 / 0.037052 (0.010766) | 0.292370 / 0.258489 (0.033881) | 0.316142 / 0.293841 (0.022301) | 0.049539 / 0.128546 (-0.079007) | 0.010533 / 0.075646 (-0.065113) | 0.058131 / 0.419271 (-0.361141) | 0.033807 / 0.043533 (-0.009725) | 0.277623 / 0.255139 (0.022484) | 0.292294 / 0.283200 (0.009094) | 0.021110 / 0.141683 (-0.120573) | 1.160997 / 1.452155 (-0.291157) | 1.213553 / 1.492716 (-0.279163) |

### Benchmark: benchmark_getitem\_100B.json

| metric | get_batch_of\_1024\_random_rows | get_batch_of\_1024\_rows | get_first_row | get_last_row |
|--------|---|---|---|---|
| new / old (diff) | 0.098220 / 0.018006 (0.080214) | 0.312342 / 0.000490 (0.311852) | 0.000231 / 0.000200 (0.000031) | 0.000052 / 0.000054 (-0.000002) |

### Benchmark: benchmark_indices_mapping.json

| metric | select | shard | shuffle | sort | train_test_split |
|--------|---|---|---|---|---|
| new / old (diff) | 0.022893 / 0.037411 (-0.014519) | 0.075572 / 0.014526 (0.061046) | 0.088357 / 0.176557 (-0.088199) | 0.126354 / 0.737135 (-0.610782) | 0.089763 / 0.296338 (-0.206575) |

### Benchmark: benchmark_iterating.json

| metric | read 5000 | read 50000 | read_batch 50000 10 | read_batch 50000 100 | read_batch 50000 1000 | read_formatted numpy 5000 | read_formatted pandas 5000 | read_formatted tensorflow 5000 | read_formatted torch 5000 | read_formatted_batch numpy 5000 10 | read_formatted_batch numpy 5000 1000 | shuffled read 5000 | shuffled read 50000 | shuffled read_batch 50000 10 | shuffled read_batch 50000 100 | shuffled read_batch 50000 1000 | shuffled read_formatted numpy 5000 | shuffled read_formatted_batch numpy 5000 10 | shuffled read_formatted_batch numpy 5000 1000 |
|--------|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| new / old (diff) | 0.284368 / 0.215209 (0.069159) | 2.785497 / 2.077655 (0.707842) | 1.499364 / 1.504120 (-0.004756) | 1.376020 / 1.541195 (-0.165175) | 1.394270 / 1.468490 (-0.074220) | 0.571945 / 4.584777 (-4.012832) | 2.419148 / 3.745712 (-1.326564) | 2.796974 / 5.269862 (-2.472887) | 1.749531 / 4.565676 (-2.816145) | 0.064088 / 0.424275 (-0.360187) | 0.005294 / 0.007607 (-0.002313) | 0.336250 / 0.226044 (0.110206) | 3.315933 / 2.268929 (1.047004) | 1.877165 / 55.444624 (-53.567459) | 1.592336 / 6.876477 (-5.284140) | 1.599979 / 2.142072 (-0.542093) | 0.655617 / 4.805227 (-4.149610) | 0.117636 / 6.500664 (-6.383028) | 0.040813 / 0.075469 (-0.034656) |

### Benchmark: benchmark_map_filter.json

| metric | filter | map fast-tokenizer batched | map identity | map identity batched | map no-op batched | map no-op batched numpy | map no-op batched pandas | map no-op batched pytorch | map no-op batched tensorflow |
|--------|---|---|---|---|---|---|---|---|---|
| new / old (diff) | 0.976887 / 1.841788 (-0.864901) | 12.668753 / 8.074308 (4.594445) | 11.081253 / 10.191392 (0.889861) | 0.134494 / 0.680424 (-0.545930) | 0.016053 / 0.534201 (-0.518148) | 0.291607 / 0.579283 (-0.287676) | 0.287726 / 0.434364 (-0.146638) | 0.328108 / 0.540337 (-0.212229) | 0.425194 / 1.386936 (-0.961742) |

</details>
</details>

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