[llvm] [Legalizer] Expand fmaximum and fminimum (PR #67301)

[Matt Arsenault via llvm-commits]

arsenm wrote:

> > Reverse ping! Are you still working on this?
> 
> Sure! Any comments I missed?

I still think we should avoid using is_fpclass here 

https://github.com/llvm/llvm-project/pull/67301