[llvm] PPC: Remove manual run of machine verifier (PR #208032)

[Matt Arsenault via llvm-commits]

arsenm wrote:

> Calling MF.verify() at the end of a non-trivial transformation to catch invariant violations introduced seem to be something that is done in other passes/platforms as well.

It should not be done by any individual pass. There are a few exceptions for the register coalescer and allocator, but that's a workaround for a pass manager + LiveIntervals issue

> Any reason why you want this specific one removed?

I ran into a verifier error in this pass and it increased the debugging effort 



https://github.com/llvm/llvm-project/pull/208032