[clang] [analyzer][Z3] Restore the original timeout of 15s (PR #118291)

[Balazs Benics via cfe-commits]

https://github.com/steakhal requested changes to this pull request.

I have no major concerns with this patch.
I proposed some wording changes, and I think we should test the configuration we had for the defaults we had prior to this patch to showcase that what is the expected behavior for the situations that motivated the Z3 oracle.

Thank you for proposing this.

https://github.com/llvm/llvm-project/pull/118291