Draft: Migrate all tests to use current code and include test validation at the CI

This MR makes all tests pass on Ubuntu 22.04 without having to bootstrap anything: PASSED (skips=2, successes=126) A new pipeline stage is created using the Ubuntu image, mainly because the tests use paths relative to a Debian installation (lib instead of lib64, for example).

The next approach would be to run the tests on each specific platform's job after the bootstrap.