[llvm] [X86] Support lowering of FMINIMUMNUM/FMAXIMUMNUM (PR #121464)

[Phoebe Wang via llvm-commits]

phoebewang wrote:

@arsenm I saw 3 failures in check-all, could you please take a look? Thanks!

```
Failed Tests (3):
  LLVM :: CodeGen/AArch64/fp-maximumnum-minimumnum.ll
  LLVM :: CodeGen/AMDGPU/maximumnum.ll
  LLVM :: CodeGen/AMDGPU/minimumnum.ll
```

https://github.com/llvm/llvm-project/pull/121464