[clang] [analyzer] Indicate UnarySymExpr is not supported by Z3 (PR #108900)

[via cfe-commits]

vabridgers wrote:

Maybe this CR could be easily improved to handle this case correctly rather than avoiding the crash, just wanted to see if it's better to get this change in for now avoiding the crash or get some advice on how to fix this correctly. 

https://github.com/llvm/llvm-project/pull/108900