[TASK] Tests: Do not extend from extbase BaseTestCase

Changes all extensions except extbase and fluid to extend
from extbase ext:core UnitTestCase instead of ext:extbase
BaseTestCase.

Change-Id: Ifbb1542546f2622ece11471fd057ec469518488a
Resolves: #56949
Related: #51436
Releases: 6.2
Reviewed-on: https://review.typo3.org/28434
Reviewed-by: Anja Leichsenring
Tested-by: Anja Leichsenring
Reviewed-by: Christian Kuhn
Tested-by: Christian Kuhn