[llvm] [SEH] Ignore EH pad check for internal intrinsics (PR #79694)

[Phoebe Wang via llvm-commits]

phoebewang wrote:

Understood! I'm back from a short vacation too :)

> I really worry that this could allow tail merging transforms that the funclet bundles are designed to prevent, something like this:

Not sure if I understood the question. It looks to me they are unrelated. The patch is to fix #69428, where a cleanup pad has more than one edges. This is intended to these [SEH intrinsics](https://llvm.org/docs/LangRef.html#llvm-seh-scope-begin-and-llvm-seh-scope-end-intrinsics) because they are used to mark a scope of instructions that may trigger cleanup for a CPP object.

I don't see any risks to normal invokes since we limited it to internal intrinsics only.

https://github.com/llvm/llvm-project/pull/79694