[clang] [llvm] [analyzer][NFC] Reorganize Z3 report refutation (PR #95128)

[Donát Nagy via cfe-commits]

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

LGTM. I didn't deeply analyze all the small details of the commit, but it is clearly NFC (builds better infrastructure for follow-up commits), the implementation is clear and elegant (slightly better quality than what I can write) and the tests demonstrate that it's working.

IMO feel free to merge this and continue with the next commit.

https://github.com/llvm/llvm-project/pull/95128