[clang] [analyzer] Hotfix a boolean conversion crash in the Z3 SMTConv (PR #158276)

[via cfe-commits]

vabridgers wrote:

Thanks @NagyDonat and @steakhal for the review comments and acknowledgements. Even characterizing these issues can be difficult, and frankly I would like to do more than just report crashes with reproducers and post half-step solutions. But we are trying to make use of these tools internally in time constrained release cycles, and crashes prevent us from enabling Z3 to refute the cases that we can. Having worked together on these issues in the past, I'm confident you understand my POV here. 

I will create a github issue to follow up on the root cause and link this PR. 


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