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

[Balázs Benics via cfe-commits]

steakhal wrote:

> > It looks like the `Analysis/inner-pointer.cpp` test fails. The PR must change the semantics of something. Could you look into this?
> 
> Thank you for pointing this out! I apologize for not catching the test failure before pushing the second time. I'll work on it and fix it.

I don't think you could have spotted this earlier. I had to approve the jobs to run. I think at that time, they were not approved yet.

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