[clang] [clang module] Current Working Directory Pruning (PR #124786)

[Michael Spencer via cfe-commits]

https://github.com/Bigcheese requested changes to this pull request.

This looks like the right approach, but I think it would be good to have a test for the relative path checking. Not every option needs a test, just one should be fine.

https://github.com/llvm/llvm-project/pull/124786