[clang] [llvm] [LLVM][Coroutines] Perform HALO on "coro_must_elide" coroutines (PR #98974)

[Chuanqi Xu via cfe-commits]

ChuanqiXu9 wrote:

It looks like the diff has some problems (it contains clang's change). And how do you think about the suggestion to split the middle end patch?

https://github.com/llvm/llvm-project/pull/98974