[llvm] [InstCombine] Fix ninf propagation for fcmp+sel -> minmax (PR #136433)

[Yingwei Zheng via llvm-commits]

dtcxzyw wrote:

I have posted an RFC for further discussion: https://discourse.llvm.org/t/rfc-clarify-the-behavior-of-select-with-fp-poison-generating-flags/85974

https://github.com/llvm/llvm-project/pull/136433