Tezt: Alcotezt (Alcotest wrapper library)

Context

This MR is a spin-off of !6760 (closed) . Depends on !7653 (merged)

It provides a wrapper above Tezt with the same interface as Alcotest, so that our Alcotest tests can be run without Alcotest, but with Tezt instead.

With this wrapper, all you have to do to migrate a test to Tezt is to modify two letters in the manifest as such:

• replace test into tezt (well technically it can be tests into tezt so it can add one more character to the diff…);
• replace alcotest into alcotezt.

It turns out that this even works for tests that use Qcheck_alcotest. We need to keep the qcheck_alcotest dependency for it to work but it shows that it should actually be straightforward to provide an equivalent module for Tezt.

Manually testing the MR

For the moment it should be consider as dead code.

Checklist

• Document the interface of any function added or modified (see the coding guidelines)
• Document any change to the user interface, including configuration parameters (see node configuration)
• Provide automatic testing (see the testing guide).
• For new features and bug fixes, add an item in the appropriate changelog (docs/protocols/alpha.rst for the protocol and the environment, CHANGES.rst at the root of the repository for everything else).
• Select suitable reviewers using the Reviewers field below.
• Select as Assignee the next person who should take action on that MR