[cleanup] remove empty test classes

[hogoww]

Multiple test classes are currently empty in a new image. This PR removes them. There was also an empty test superclass.

Let me know if something may be an issue.

[hogoww]

Failing test cases are related, I'll take a look and document them

[hogoww]

One test case failed in the CI, unrelated. I'll let better people than me judge whether this clean up makes sense. I don't see much incentive of keeping empty test classes, but I'm sure I could find reasons.