[llvm] [X86] Set up the framework for optimization of CCMP/CTEST (PR #84603)

[Shengchen Kan via llvm-commits]

KanRobert wrote:

Compared with this implementation, DAGCombine + pattern match approach can not handle two cases at least.  See comments at https://github.com/llvm/llvm-project/pull/91747

I believe we should add this MIR pass and handle the missed cases with DAGCombine + pattern match approach if we find it in real world. 

https://github.com/llvm/llvm-project/pull/84603