[llvm] [GlobalISel][AMDGPU][AArch64] Fix GlobalISel copy propagation (PR #188781)

[Jay Foad via llvm-commits]

https://github.com/jayfoad commented:

I think this is OK overall. My only reservation is that I don't understand the AArch64 selectCopy implementation, so it would be good if @davemgreen or another maintainer could sign off on that.

https://github.com/llvm/llvm-project/pull/188781