Reapply "[coro][CoroSplit] Use `llvm.lifetime.end` to compute putting objects...

Reapply "[coro][CoroSplit] Use `llvm.lifetime.end` to compute putting objects on the frame vs the stack (#90265) (#91372)

This reverts commit 92438416.

This reland addresses the performance regressions seen in #90265 by
retaining the original definition of
`isPotentiallyReachableFromMany(...)` instead of reimplementing it with
`isManyPotentiallyReachableFromMany(...)`.

Fixes #86580