[Pipelines] Hoist CoroCleanup to avoid blocking optimizations

CoroCleanup is designed to lowering all the remaining coroutine
intrinsics. It is required to run after CoroSplit only. However, the
position of CoroCleanup now is far too late. The downside here is that
the unlowered coroutine instrincs might blocking other optimizations
too. So it should be a pure win to hoist the position of CoroCleanup.

Reviewed By: aeubanks

Differential Revision: https://reviews.llvm.org/D124360