[clang] [analyzer] Fix taint sink rules for exec-like functions (PR #66358)

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

Hmm, let's just merge this.

My only concern was that I felt that running a tainted executable is significantly more problematic than passing tainted command-line arguments to a trusted executable, but you're right that even a tainted command-line argument is still as risky as other things that we handle as taint sinks.

https://github.com/llvm/llvm-project/pull/66358