[llvm] [Coro] [async] Disable inlining in async coroutine splitting (PR #80904)

[Jeff Niu via llvm-commits]

Mogball wrote:

Hmm. It seems this is breaking compilation of async coroutines when the calling convention is not `swifttailcc`. `musttail` for functions that aren't `swifttailcc` are required to match in prototype the callee (which is assumed to be the surrounding function). However, the coroutine splitting is generating a musttail call to another function. We worked around this by tagging our functions as `swifttailcc`, but this doesn't seem right?

https://github.com/llvm/llvm-project/pull/80904