[llvm] expandFMINNUM_FMAXNUM: Improve for backends with FMINIMUMNUM and FMINNUM_IEEE (PR #181083)

[YunQiang Su via llvm-commits]

wzssyqa wrote:

> I _think_ there's more leeway for `FMINNUM` and `FMAXNUM` now.

I fully agree. I think that we can do something like we had done for fminimum and fminimumnum:
  * work with NaNs
  * work with signed zeros.
to reduce the libc calls and fully compatible with C23.

https://github.com/llvm/llvm-project/pull/181083