[Coroutines] Always set the calling convention of generated resuming call from...

[Coroutines] Always set the calling convention of generated resuming call from 'llvm.coro.await.suspend.handle' as fast (#93167)

See the post commit message in
https://github.com/llvm/llvm-project/pull/89751

We met a regression due to a change of calling convention of this patch.
Previously, the calling convention of indirect resume calls is always
fast.

And in this patch, although we tried to take care of it in the cloner,
we forget the case that we have to update the resuming calls in the ramp
functions. So this is the root cause of the downstream failure.

This patch tries to mark the generated resuming calls as fast
immediately after they got created to make sure the calling convention
is correct.