[clang-tools-extra] [clang-tidy] give dummy path when create ClangTidyContext (PR #134670)

[Carlos Galvez via cfe-commits]

https://github.com/carlosgalvezp approved this pull request.

This should work, thanks! I still feel the whole framework needs a bit of refactoring, the logic and data flow is a bit hidden and it's hard to spot these dependencies that break because things are done in the wrong order.

https://github.com/llvm/llvm-project/pull/134670