[llvm] [BOLT] Gadget scanner: improve handling of unreachable basic blocks (PR #136183)

[Kristof Beyls via llvm-commits]

https://github.com/kbeyls commented:

Thanks, this mostly looks OK to me. I only have one comment, wondering about whether the warning message that gets produced could be improved a bit.

https://github.com/llvm/llvm-project/pull/136183