Reorder split names

Reorder split names in the YAML metadata to be aligned with the order in the loading script.
See: https://github.com/huggingface/datasets/issues/5258

README.md

@@ -42,12 +42,12 @@ dataset_info:
     - name: number
       dtype: int32
   splits:
-  - name: test
-    num_bytes: 40269203
-    num_examples: 7500
   - name: train
     num_bytes: 236605152
     num_examples: 38969
+  - name: test
+    num_bytes: 40269203
+    num_examples: 7500
   - name: validation
     num_bytes: 41543528
     num_examples: 6327