Abstract access to `nextTick()` in Jest tests into a utility function

This is about craziness like wrapper.vm.nextTick() and it's bad-brother vm.vm.nextTick().

The following discussion from !999 (merged) should be addressed:

• @ntepluhina started a discussion: (+1 comment)

  nitpick: out of the scope of the MR but vm.vm is triggering me so much 😅 could we use something like wrapper in future tests to distinguish VTU Wrapper from the actual Vue instance?

One of the possible solutions: manually update all suits with the suggestion from !999 (merged).

However, a more abstract universal utility shared between all suits automatically would be preferable.