[windows] Enable SourceKit tests in CI.

[drodriguez]

Small change to see what's broken in the community CI.

[drodriguez]

@swift-ci please clean test Windows platform

[gmittert]

I know there are still a handful of broken Sourcekit tests on Windows locally on my machine:

Failing Tests (11):
    Swift(windows-x86_64) :: SourceKit/CodeComplete/injected_vfs.swift
    Swift(windows-x86_64) :: SourceKit/CodeComplete/injected_vfs_complete_open.swift
    Swift(windows-x86_64) :: SourceKit/CodeComplete/injected_vfs_swiftinterface.swift
    Swift(windows-x86_64) :: SourceKit/CompileNotifications/code-completion.swift
    Swift(windows-x86_64) :: SourceKit/CompileNotifications/type-context-info.swift
    Swift(windows-x86_64) :: SourceKit/CursorInfo/injected_vfs.swift
    Swift(windows-x86_64) :: SourceKit/Sema/injected_vfs.swift
    Swift(windows-x86_64) :: SourceKit/Sema/injected_vfs_after_edit.swift
    Swift(windows-x86_64) :: SourceKit/Sema/injected_vfs_sourcetext.swift
    Swift(windows-x86_64) :: SourceKit/Sema/sema_playground.swift
    Swift(windows-x86_64) :: SourceKit/SyntaxMapData/diags.swift

By my count, but I'm good to enable these on the Windows CI so we can see that they're broken

[gmittert]

@swift-ci please smoke test

[gmittert]

Looks like there are 3 fewer failures than I have locally so that's good. I believe the notification tests and the playground test fail because it generates an error message for both S:\... and C:\... when it only expects on error and it might not do that on CI depending on how it's set up.

[drodriguez]

I think I have a small fix for the diags.swift one which should be isolated, and hopefully doesn’t create more problems.

It is good that the sed problems I was having doesn’t happen in this case.

I also think that the %drive changes in the test might get the VFS failures down to 2 or 3 (one of them probably SourceKit/CodeComplete/injected_vfs_swiftinterface.swift)

[drodriguez]

Included as part of #28250.