[clang] [analyzer] Fix performance of getTaintedSymbolsImpl() (PR #89606)

[Balazs Benics via cfe-commits]

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

Thanks!

The patch makes sense. Thank you for the promptly fix.
I've checked and this resolves the `FFmpeg` issue.
i wonder if this is serious enough to consider hangs as a crash and nominate this PR for backport to `clang-18`.
Leave me no doubt, we will have it downstream for sure, but upstream users might wanna also have this.
@Xazax-hun WDYT?

https://github.com/llvm/llvm-project/pull/89606