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

[YunQiang Su via llvm-commits]

wzssyqa wrote:

Yes, currently it is not consistent between architectures, and I am working to fix them.
Since we cannot implement them in a single so huge patch, we need update the docs and then the code.

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