[llvm] [AArch64] Run cleanup one final time after peephole (PR #199711)

[via llvm-commits]

AZero13 wrote:

> The test changes seem to be mostly caused by not removing dead copies that could be cleaned up as part of the peephole pass. It could also rejig the pipeline so that AArch64 MI Peephole opt is ran before Remove dead machine, either way I would recommend reverting this as we needn't pay such a high price for something so minor.

Is the price THAT high? If so I can figure out how to not run it twice and have a PR in like an hour or so. 

https://github.com/llvm/llvm-project/pull/199711