[clang] [Clang] Implement P2843R3 - Preprocessing is never undefined (PR #192073)

[Corentin Jabot via cfe-commits]

cor3ntin wrote:

Presumably microsoft gets confused by their own code
https://developercommunity.visualstudio.com/t/issue-in-windows-sdk-header/383016 

It might be worth considering making it a warning instead, that would get silence in system headers.
@AaronBallman do warning-as-error get silenced? I don't recall but that might be a good solution

https://github.com/llvm/llvm-project/pull/192073