[clang] [analyzer] Correct crash in Z3 wrapper (PR #158276)

[via cfe-commits]

vabridgers wrote:

I'll rework this change a bit more and update. Turns out the test case I chose to add these cases is for z3 as a constraint manager, not refutation. These cases were discovered using z3 for refutation, so will require some rework to the PR. Thanks for the comments.

https://github.com/llvm/llvm-project/pull/158276