[clang] [llvm] [mlir] [Coroutines] Add llvm.coro.is_in_ramp and drop return value of llvm.coro.end (PR #153404)

[Chuanqi Xu via llvm-commits]

ChuanqiXu9 wrote:

I reverted it as the failure seems relevent.

https://github.com/llvm/llvm-project/pull/153404