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

[via llvm-commits]

valadaptive wrote:

> This is confused. The new definition better matches IEEE, which is what was actually built into hardware.

x86, at least, does not implement signed-zero ordering the way the "new definition" describes it.

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