[windows] move windows-llvm-lit-test-overrides.txt to the llvm-project repository

[charles-zablit]

This patch moves the file windows-llvm-lit-test-overrides.txt from swiftlang/swift to swiftlang/llvm-project.

As it controls the failing and skipped tests of LLVM, this will make it easier to remove tests that are no longer failing as we improve the test coverage of LLDB on Windows.

This should be merged before swiftlang/swift#83588.

[charles-zablit]

@swift-ci please test

[weliveindetail]

Seems reasonable

[weliveindetail]

Maybe the new name should reflect that the overrides are Swift specific. This was obvious in the old location. In the new location it's obvious that this file if relevant for llvm LIT test. It's also not clear anymore where to find build.ps1.

[charles-zablit]

Fixed, thanks!

[charles-zablit]

To explain the motivation, consider #11096. It's failing because it fixes 2 tests which are marked as xfail in windows-llvm-lit-test-overrides.txt. There is a chicken and egg problem where we have to remove the xfail in swiftlang/swift and then cherry-pick to release/6.2. However that would cause the CI to fail while we merge #11096.

This patch removes this problem altogether.

[charles-zablit]

@swift-ci please test

[compnerd]

We should make sure that the appropriate version is also merged into stable/21.x. (CC: @AnthonyLatsis @bnbarham)