[clang] [Analyzer] No longer crash with VLA operands to unary type traits (PR #151719)

[Aaron Ballman via cfe-commits]

AaronBallman wrote:

> Hold on, the issue you fixed here was only opened like 30 minutes ago, how did you patch this in just 10 minutes?

I happened to triage the issue and went "I wonder what's going on?" then saw what was happening and realized "I just had to do this dance for `_Countof` and I think I missed this spot". :-D

https://github.com/llvm/llvm-project/pull/151719