[TASK] Clean up Unit tests in extbase

We had many tests in extbase that are incomplete.
These tests has been incomplete for several years.

Some test has been removed also in TYPO3 flow.

Change-Id: I75a20d1a1bac6fdeca79067acd5d00ad2db9f964
Fixes: #45330
Releases: 6.1
Reviewed-on: https://review.typo3.org/18169
Reviewed-by: Christian Kuhn
Tested-by: Christian Kuhn
Reviewed-by: Wouter Wolters
Reviewed-by: Oliver Klee
Reviewed-by: Anja Leichsenring
Tested-by: Anja Leichsenring