[clang] [StaticAnalyzer] Fix InnerPointerBRVisitor to avoid repeated map scans (PR #185796)

[Benedek Kaibas via cfe-commits]

benedekaibas wrote:

> Shall we close this?

I am thinking about just removing the comment as @Xazax-hun mentioned in his reply and opening a new PR for that.

https://github.com/llvm/llvm-project/pull/185796