[clang] [analyzer][z3] Fix crash in Z3 SMTConv when casting atomic int (PR #211489)

[Balázs Benics via cfe-commits]

steakhal wrote:

@guillem-bartrina-sonarsource Do you have a CPP tracker number for this that I should include in the commit message?

https://github.com/llvm/llvm-project/pull/211489