[clang] [LifetimeSafety] Fix crash on ternary operator when one of the expressions is `throw` (PR #190345)

[via cfe-commits]

NeKon69 wrote:

So what approach would you consider the best one in the end? The second one (which is supposed to be the "simple" one, although I can't get it to work for some reason) Or the first one, where I would have to modify `CFGBlock`?

https://github.com/llvm/llvm-project/pull/190345