[llvm] Revert "LangRef: Clarify llvm.minnum and llvm.maxnum about sNaN and signed zero (#112852)" (PR #138451)

[Matt Arsenault via llvm-commits]

https://github.com/arsenm requested changes to this pull request.

The operation is fundamentally broken. You cannot handwave signaling nans away like other operations. We are not going to make forward progress unless we fix the definition. Signaling nans do not matter in the slightest in the real world. I do not consider any signaling validation failure to be an emergency worth reverting over 

https://github.com/llvm/llvm-project/pull/138451