[llvm] [GISel][AArch64] Create emitCMP instead of cloning a virtual register (NFC) (PR #155262)

[David Green via llvm-commits]

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

Thanks. You could do it in these other emit.. functions too if you wanted.

LGTM.

https://github.com/llvm/llvm-project/pull/155262