[clang] [clang][Dependency Scanning] Adding an API to Diagnose Invalid Negative Stat Cache Entries (PR #135703)

[Qiongsi Wu via cfe-commits]

qiongsiwu wrote:

Note to reviewers:
I am not quite sure if passing in the underlying VFS is a good design. If I understand correctly, the underlying VFS is a dependency scanning worker property, so on the surface it seems that we will need this diagnostic per worker, instead of per scanning service. 

I am all ears for a different design. 

https://github.com/llvm/llvm-project/pull/135703