[llvm] [NFC][LV] Introduce enums for uncountable exit detail and style (PR #184808)

[Sander de Smalen via llvm-commits]

sdesmalen-arm wrote:

Just as a general comment, it would have been useful if you'd made this into a stacked PR (this PR at the bottom with #183318 and  #178454 rebased on top). It's a bit hard to follow what the dependences are otherwise.

https://github.com/llvm/llvm-project/pull/184808