Most of tests (inherited from CacheMvccAbstractTest) run vacuum synchronously on afterTest() method and check if vacuum is ok. This hits performance, can cause false negative results and
vacuum issues can be hidden if afterTest method will overriden at once.
For now we have CacheMvccVacuumTest that just check vacuum workers state, but there is no check if vacuum really cleans all old versions correctly. I'd expect to find it in this class.
So, let's mode vacuum verification from afterTest method into CacheMvccVacuumTest as a new separate test.