[clang] [analyzer] Avoid crashes in the stream checker (PR #100901)

[Balazs Benics via cfe-commits]

steakhal wrote:

Thanks for the really valuable reduced case @vabridgers. I'll close this in favor of #100990 if you don't mind.
Thanks again for reporting the crash.

https://github.com/llvm/llvm-project/pull/100901