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

[Donát Nagy via cfe-commits]

https://github.com/NagyDonat commented:

Do I understand it correctly that this deficiency affects the standalone Z3 analysis mode (as opposed to the "Z3 refutation" where the analysis is performed with the native range-based constraint manager, and then the results are validated with Z3 to discard the logically impossible paths)?

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