[clang] [analyzer][Solver] Early return if sym is concrete on assuming (PR #115579)

[Balazs Benics via cfe-commits]

steakhal wrote:

I see your point, but I'm still not convinced.
Anyways, that's partially beyond this PR. What we have here I can completely agree with. I just have the feeling it solved one particular case, and not a class of bugs - which is fine.

https://github.com/llvm/llvm-project/pull/115579