[llvm] [RISCV] Move MachineCombiner to addILPOpts() (PR #158071)

[Anton Sidorenko via llvm-commits]

https://github.com/asi-sc approved this pull request.

lgtm. As it was mentioned in the issue, my measurements several years ago showed that the original pass placement provided better performance. But I have no bandwidth to re-measure the current state, so I'm happy with the change if it fixes known perf issue and do not introduce new ones (at least we do not see them right now).

https://github.com/llvm/llvm-project/pull/158071