[clang] [clang][analyzer] Add checker 'security.SetgidSetuidOrder'. (PR #91445)

[Donát Nagy via cfe-commits]

https://github.com/NagyDonat commented:

Thanks for updating your commit! Now there are only two remaining issues and they are both very minor (marked by inline comments: renaming `CallExpr *CE` and explaining the reason why "trying to set the gid again" appears as a special case in the SEI-CERT standard).

https://github.com/llvm/llvm-project/pull/91445