[llvm] CodeGen: Strengthen definition of F{MIN|MAX}NUM_IEEE nodes (PR #85195)

[Matt Arsenault via llvm-commits]

arsenm wrote:

> Will some target be an exception of such assumption?

Probably, but the point of these intermediates is legalization aid since we don't directly expose them so the point is to match whatever hardware behavior is. We can introduce more variants as necessary 



https://github.com/llvm/llvm-project/pull/85195