[clang] [llvm] Reland "[X86] Remove knl/knm specific ISAs supports (#92883)" (PR #93136)

[Freddy Ye via llvm-commits]

FreddyLeaf wrote:

any idea on why `Labelling new pull requests / greeter (pull_request_target)` is **skipped**? @phoebewang @RKSimon 

https://github.com/llvm/llvm-project/pull/93136