[llvm] [Coroutines][LazyCallGraph] resumes are not really SCC (PR #116285)

[John McCall via llvm-commits]

rjmccall wrote:

That sounds roughly right. There's no need to add a reference back to the initial funclet in any lowering, and the switch lowering only strictly needs to ref the two new funclets from the initial funclet, but otherwise, adding a ref from every funclet to every non-initial funclet is definitely the conservatively correct way to handle all of the lowerings that use non-unified continuations (which is everything but the switch lowering).

https://github.com/llvm/llvm-project/pull/116285