'search files' popup should favor case-sensitive matches
Issue Type: <b>Bug</b>

I have two files in my project in different locations. `HTTPClient.cpp` and `HttpClient.cpp`.

The 'search in files' popup always shows `HTTPClient` first, event when searching for the latter:

![image](https://user-images.githubusercontent.com/1088194/136674158-8ab523c2-8b77-45b3-9145-806c56be88c6.png)

please include case-sensitivity in the sort function for this.

VS Code version: Code 1.60.2 (7f6ab5485bbc008386c4386d08766667e155244e, 2021-09-22T12:00:31.514Z)
OS version: Windows_NT x64 10.0.19043
Restricted Mode: No
Remote OS version: Linux x64 5.10.16.3-microsoft-standard-WSL2
Remote OS version: Linux x64 5.10.16.3-microsoft-standard-WSL2
Remote OS version: Linux x64 5.10.16.3-microsoft-standard-WSL2
Remote OS version: Linux x64 5.10.16.3-microsoft-standard-WSL2

<details>
<summary>System Info</summary>

|Item|Value|
|---|---|
|CPUs|Intel(R) Core(TM) i5-9400 CPU @ 2.90GHz (6 x 2904)|
|GPU Status|2d_canvas: enabled<br>gpu_compositing: enabled<br>multiple_raster_threads: enabled_on<br>oop_rasterization: enabled<br>opengl: enabled_on<br>rasterization: enabled<br>skia_renderer: enabled_on<br>video_decode: enabled<br>vulkan: disabled_off<br>webgl: enabled<br>webgl2: enabled|
|Load (avg)|undefined|
|Memory (System)|47.66GB (14.45GB free)|
|Process Argv|--crash-reporter-id 70645636-42ae-4864-b371-1810b42a2956|
|Screen Reader|no|
|VM|0%|

|Item|Value|
|---|---|
|Remote|WSL: CentOS7|
|OS|Linux x64 5.10.16.3-microsoft-standard-WSL2|
|CPUs|Intel(R) Core(TM) i5-9400 CPU @ 2.90GHz (6 x 2904)|
|Memory (System)|37.35GB (11.26GB free)|
|VM|0%|

|Item|Value|
|---|---|
|Remote|WSL: CentOS7|
|OS|Linux x64 5.10.16.3-microsoft-standard-WSL2|
|CPUs|Intel(R) Core(TM) i5-9400 CPU @ 2.90GHz (6 x 2904)|
|Memory (System)|37.35GB (11.26GB free)|
|VM|0%|

|Item|Value|
|---|---|
|Remote|WSL: CentOS7|
|OS|Linux x64 5.10.16.3-microsoft-standard-WSL2|
|CPUs|Intel(R) Core(TM) i5-9400 CPU @ 2.90GHz (6 x 2904)|
|Memory (System)|37.35GB (11.26GB free)|
|VM|0%|

|Item|Value|
|---|---|
|Remote|WSL: CentOS7|
|OS|Linux x64 5.10.16.3-microsoft-standard-WSL2|
|CPUs|Intel(R) Core(TM) i5-9400 CPU @ 2.90GHz (6 x 2904)|
|Memory (System)|37.35GB (11.26GB free)|
|VM|0%|
</details><details><summary>Extensions (5)</summary>

Extension|Author (truncated)|Version
---|---|---
jupyter-keymap|ms-|1.0.0
remote-ssh|ms-|0.65.8
remote-ssh-edit|ms-|0.65.8
remote-wsl|ms-|0.58.2
hexeditor|ms-|1.8.2


</details><details>
<summary>A/B Experiments</summary>

```
vsliv368cf:30146710
vsreu685:30147344
python383:30185418
pythonvspyt602:30300191
vspor879:30202332
vspor708:30202333
vspor363:30204092
vswsl492cf:30256860
pythonvspyt639:30300192
pythontb:30283811
pythonptprofiler:30281270
vsdfh931cf:30280410
vshan820:30294714
vstes263:30335439
vscorecescf:30358481
pythondataviewer:30285071
pythonvsuse255:30340121
vscod805:30301674
pythonvspyt200:30340761
binariesv615:30325510
vsccppwtct:30378365
pythonvssor306:30344512
bridge0708:30335490
pygetstartedt2:30371810
dockerwalkthru:30377721
bridge0723:30353136
pythonrunftest32:30373476
pythonf5test824:30373475
javagetstartedc:30364665
pythonvspyt187:30373474
pydsgst2:30361792
vsqsis200:30374795
vsaa593cf:30376535

```

</details>

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