What

fix cram test output following dune changes in 3.19.0 and 3.19.1
require dune 3.19.1 because of that too
remove test that behaves differently in OCaml 5.3.0

Why

So that we can merge other, unrelated merge requests.

How

Manually testing the MR

Checklist

Update CHANGES.md. No need to document changes to documentation and tests.
Make sure all new values, types etc. are documented in .mli files and that the generated documentation looks ok.
Add tests in test/, if relevant.