[clang] [Analysis] Avoid some warnings about exit from noreturn function (PR #144408)

[Erich Keane via cfe-commits]

https://github.com/erichkeane commented:

A couple of nits, else I think this is reasonable.  I want Aaron to do final approval though, as he has some good suggestions/a broken mind when it comes to repros :) 

https://github.com/llvm/llvm-project/pull/144408