[clang] [NFC][analyzer] Extract general logic in security.ArrayBound (PR #210774)

[Donát Nagy via cfe-commits]

NagyDonat wrote:

> > I started a CI job to also validate the NFCness of this PR on our set of open source projects.
> 
> I'm glad that I followed procedure and started this CI job because it revealed that **this PR is not NFC**, the set of results had changed on many open source projects.
> 
> I will analyze the CI results and fix the NFCness of this PR.

This was a straightforward false alarm: there was a merge commit on this branch, so the CI comparison included lots of unrelated commits (so it is not surprising that they change the result set). I will redo the CI analysis, comparing the PR to the right baseline.

https://github.com/llvm/llvm-project/pull/210774