[llvm] [ConstantFolding] Fold vector reduce `fmax` and `fmin` intrinsics (PR #143904)

[Craig Topper via llvm-commits]

topperc wrote:

> minnum/maxnum are not safe to reassociate due to the signaling nan behavior

Do we are about SNANs in the default FP environment?

https://github.com/llvm/llvm-project/pull/143904