[llvm] [IR] Introduce hash_value for FMF, GEPNoWrapFlags (PR #151946)

[Florian Hahn via llvm-commits]

https://github.com/fhahn commented:

I don't think that's needed. Same as IR CSE, we should drop the flags when re-using a value

https://github.com/llvm/llvm-project/pull/151946