[clang] [StaticAnalyzer] Fix state update in VisitObjCForCollectionStmt (PR #124477)

[Balazs Benics via cfe-commits]

https://github.com/steakhal commented:

This change affects how an AST node is modeled. Consequently, it's a core change.
As such a change, we should have a test.

Overall, I really liked how thoroughly you described what caused the issue, and that helped to justify the fix. On that front, it looks great.

Thank you for your contribution.

https://github.com/llvm/llvm-project/pull/124477