[llvm] [X86][GlobalIsel] Reland G_ISFPCLASS (PR #165848)

[via llvm-commits]

mahesh-attarde wrote:

To unblock on this issue, i will continue working on https://github.com/llvm/llvm-project/issues/171992  and move forward with fpclass related PR.

https://github.com/llvm/llvm-project/pull/165848