[clang] [InstCombine] Add combines/simplifications for `llvm.ptrmask` (PR #67166)

[Florian Hahn via cfe-commits]

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@@ -183,8 +183,7 @@ define <16 x i8> @ptrmask_align8_ptr_align1(ptr align 1 %ptr) {
 ; TODO: Should be able to drop the ptrmask
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fhahn wrote:

remove TODO now?

https://github.com/llvm/llvm-project/pull/67166