Capital letters in workspace path cause search results duplicated under Other Files

[bluemonkmn]

Issue Type: Bug

1. Create a Visual Studio Code Workspace file.
2. Enter or change one of the letters in the path in the workspace file's "folders" section to be a capital letter (using a text editor).
3. Open the workspace in VS Code
4. Open a file from within the workspace folder
5. Perform a global search (Ctrl-Shift-F) for some text in the file

Expected Result:
The result should appear once for the opened file in the workspace-relative path

Observed result:
The result appears twice, once in the workspace-relative path, and once under "Other Files" with the fully qualified path in lowercase.

VS Code version: Code 1.44.2 (ff91584, 2020-04-16T16:36:23.138Z)
OS version: Windows_NT x64 10.0.17763

System Info

Item	Value
CPUs	Intel(R) Core(TM) i7-8850H CPU @ 2.60GHz (12 x 2592)
GPU Status	2d_canvas: enabled flash_3d: enabled flash_stage3d: enabled flash_stage3d_baseline: enabled gpu_compositing: enabled multiple_raster_threads: enabled_on oop_rasterization: disabled_off protected_video_decode: enabled rasterization: enabled skia_renderer: disabled_off_ok video_decode: enabled viz_display_compositor: enabled_on viz_hit_test_surface_layer: disabled_off_ok webgl: enabled webgl2: enabled
Load (avg)	undefined
Memory (System)	31.74GB (12.25GB free)
Process Argv	C:\landmark\ben1\Shortcuts\ben1.code-workspace
Screen Reader	no
VM	0%

Extensions (11)

Extension	Author (truncated)	Version
atlascode	atl	2.5.1
accurev	blu	0.1.0
lpl-outline	blu	0.1.5
indentation-level-movement	kai	1.3.0
lpl-language-debugger	Bel	0.1.1
lpl-language-server	Bel	1.6.2
rainbow-csv	mec	1.7.0
csharp	ms-	1.21.17
vscode-typescript-tslint-plugin	ms-	1.2.3
vscode-yaml	red	0.7.2
vscodeintellicode	Vis	1.2.6

[roblourens]

This is basically covered by #12448