[clang] [analyzer] Add support for consteval in ConditionBRVisitor::VisitTerminator (PR #146859)

[Balazs Benics via cfe-commits]

steakhal wrote:

> Hey, could you add a LIT test that fails before your changes but passes after?

Merge it once you are good. The added test should crash the analyzer without the fix, [see](https://godbolt.org/z/jxTMnGEY7).

https://github.com/llvm/llvm-project/pull/146859