Editors are identified case-sensitively on case-insensitive file systems leading to multiple editors for the same underlying file

[jacobdufault]

• VSCode Version: 1.8.1
• OS Version: Windows 10

Steps to Reproduce:

On Windows:

1. Open the same file twice via the command line but using different case, ie, code foo and code FOO.
2. There will be two editors open despite being backed by the same underlying file.

This is not limited to just the command line API, ie, a debugger can open up a file with a different case than what is present on the file-system which ends up causing breakpoints to not display properly.

[bpasero]

#12448