[llvm] Revert "LangRef: Clarify llvm.minnum and llvm.maxnum about sNaN and signed zero (#112852)" (PR #168838)

[Phoebe Wang via llvm-commits]

phoebewang wrote:

Thanks @RalfJung ! I'll merge it in the next week if no other objections.

https://github.com/llvm/llvm-project/pull/168838