[clang] [CIR] Add cir.ptr_mask (PR #224143)

[Erich Keane via cfe-commits]

https://github.com/erichkeane approved this pull request.

Approve after the `let llvmOp` change plus removing the 'matchAndRewrite' function in LowerToLLVM.

https://github.com/llvm/llvm-project/pull/224143