Move verification out into separate script to fix ARM64 use

[ell1e]

Some platforms don't have the clang sanitizer checks available that are used in the verification tests, currently on these the output files can't even be amalgamated. To fix this, separate amalgamation and verification so that the later can be skipped. Fixes #273

[ell1e]

If anyone knows why the fuzzing workflow suddenly can't find miniz_export.h anymore lemme know, I thought I hadn't moved anything around that could possibly break that (this file should still be generated by test.sh after my pull request is applied) so I don't understand what's going on there. Or is the workflow just generally broken? I can't quite make sense of it.

I would really love for this whole ARM64 musl-libc situation to get fixed soon, because it's just quite cumbersome to work around and I'm starting to shift a lot of my projects to more heavily support various ARM64 variants.

[ell1e]

If a77af68 was the reason why CIFuzz / Fuzzing failed then maybe this is still good to go in. Sadly I don't know how to trigger the build again to test if it works now. Nevertheless, the underlying problem with platforms without libsanitize support seems to remain.