[TASK] Shorten the extend class in all unit tests

Shorten \TYPO3\TestingFramework\Core\Unit\UnitTestCase to UnitTestCase

Resolves: #86478
Releases: master
Change-Id: I5dc7704fb2776cff26f1bbf89b35e28fecd9a79e
Reviewed-on: https://review.typo3.org/58501


Tested-by: TYPO3com <no-reply@typo3.com>
Reviewed-by: Stefan Neufeind <typo3.neufeind@speedpartner.de>
Tested-by: Stefan Neufeind <typo3.neufeind@speedpartner.de>
Reviewed-by: Christian Kuhn <lolli@schwarzbu.ch>
Tested-by: Christian Kuhn <lolli@schwarzbu.ch>