py2ml: replace `test_contract_input_input` from `test_contract_opcodes.py` with tezt

Context

This one is for the stats. Remove 1.5KLOC python in one fell swoop.

Manually testing the MR

test -f contract_opcodes.ml

To review the last 3 commits, consider the git command:

git show -Ioctez-client HEAD..HEAD~2 -M20%

For me, this shows all traces as renames. The exception is the contracts related to LEVEL. Mockup mode, that is used in the tezt versino, uses another dummy chain id, and the traces were updated to follow.

We use an uninitialized mockup mode: this let's us split tests, parallelize without having to share state between tests. The disadvantage is the mockup mode warning that shows up in all new traces. To silence these warning, a new flag --no-base-dir-warnings is added to octez-client.

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