[clang] [analyzer] Fix crash of StreamChecker when eval calling 'fopen' (PR #100990)

[Balázs Kéri via cfe-commits]

https://github.com/balazske approved this pull request.

This looks good now, documentation could be a bit more exact in that operations on standard streams are not checked by the checker, like any other operation on streams that are not opened on the analysis path.

https://github.com/llvm/llvm-project/pull/100990