[llvm] [AMDGPU] Add target hook to isGlobalMemoryObject (PR #112781)

[via llvm-commits]

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

Since this fixes a serious issue with IGLP correctness, I think it should be merged until we come up with an appropriate property to describe these instructions (that doesn't require the isIGLPInstr function). That's just my opinion.

https://github.com/llvm/llvm-project/pull/112781