[libunwind] [libunwind] Fix execution flow imbalance when using C++ Exceptions (PR #165066)

[Oliver Hunt via cfe-commits]

ojhunt wrote:

Ugh, I just checked and it looks like the codegen is wrong so assembly it will have to be, but that will at least not be templates. Will write it later. Gnah.

https://github.com/llvm/llvm-project/pull/165066