VFS is returning lower-case values for mixed-case paths

[bobbystacksmash]

The VFS should perform case-insensitive actions, which it seems to do. However, when querying the file system using methods which return string-paths for file/folder names, the names are returned in lower-case only, even for mixed-case file/folders. For example:

We add the folder FooBar:
vfs.AddFolder("C:\\Hello\\FooBar");

When fetching this file, FooBar becomes foobar:
vfs.FindFiles("C:\\Hello", "FooBar"); // => ["foobar"]

While this isn't technically a problem because Windows' FS handling is case-insensitive by default, it's conceivable that usercode may expect the case to be returned correctly (such as string comparisons for file/folder paths).

[bobbystacksmash]

A technique which may be applicable here was done in runtime/virtreg.js. See the resolve_path method which uses a dictionary to map original keys to their normalised values.