[TASK] Update testing framework to 6.0

The testing framework has been reworked and slimmed down.
To make use of it, tests had to be adjusted.

   composer require --dev typo3/testing-framework:"~6.0.0"

Resolves: #89815
Releases: master
Change-Id: Ib0a8d7436070ef17be96a5f4011f796dd15b09fd
Reviewed-on: https://review.typo3.org/c/Packages/TYPO3.CMS/+/62502


Tested-by: TYPO3com <noreply@typo3.com>
Tested-by: Georg Ringer <georg.ringer@gmail.com>
Tested-by: Benni Mack <benni@typo3.org>
Reviewed-by: Georg Ringer <georg.ringer@gmail.com>
Reviewed-by: Benni Mack <benni@typo3.org>