[clang] [analyzer][StackAddrEscapeChecker] Fix assert failure for alloca regions (PR #109655)

[Balazs Benics via cfe-commits]

https://github.com/steakhal commented:

Please mark the line in the test with `no-crash` where previously crashed.

Speaking of the fix, I think anything is better than a crash, but I wonder if we could do more.
To me, once an alloca region goes out of scope, that should behave just as if a regular stack variable, and raise an issue. What is it not the case here?

https://github.com/llvm/llvm-project/pull/109655