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

[Nikita Popov via llvm-commits]

https://github.com/nikic approved this pull request.

The CFG changes LGTM. I assume the coroutine changes have already been previously reviewed.

https://github.com/llvm/llvm-project/pull/91372