[clang] [analyzer] Fix crash in PthreadLockChecker by detecting infeasiblity early (PR #210912)

[Balázs Benics via cfe-commits]

steakhal wrote:

Right, I should have expressed what I mean by updating the title.
IMO the main product here is that we touch the solver - that it fixes a crash that materialized in a checker is just a second degree side-effect. The fact that the checker happens to be a pthreadlock, is a 3rd degree side-effect.

So I'd probably stress on pruning infeasible states in some way but I don't have more constructive examples.
Of course in the description it's a fair game to relate this to the checker.

https://github.com/llvm/llvm-project/pull/210912