[libunwind] [libunwind][PAC] Defang ptrauth's PC in valid CFI range abort (PR #184041)

[Oliver Hunt via cfe-commits]

ojhunt wrote:

> Can we write a test for this? I'd rather have a test, even if non-portable, than nothing at all.

I've tried but I think it requires some kind of jit set up to trigger. I'll try a few other terrible/hacky options but so far no luck.

https://github.com/llvm/llvm-project/pull/184041