[TASK] Merge test splitter scripts to core

The acceptance and functional test splitter scripts
from typo3/testing-framework are tailored for core
specific needs and of rather little use for non-core.

For the sake of a more clean typo3/testing-framework,
the patch merges the scripts into core mono-repo.

Change-Id: Iefb576bb52c238ccca7b618fa6f9ea0d5718d0f9
Resolves: #93586
Releases: master, 10.4
Reviewed-on: https://review.typo3.org/c/Packages/TYPO3.CMS/+/68098


Tested-by: TYPO3com <noreply@typo3.com>
Tested-by: core-ci <typo3@b13.com>
Tested-by: Anja Leichsenring <aleichsenring@ab-softlab.de>
Tested-by: Benni Mack <benni@typo3.org>
Tested-by: Andreas Fernandez <a.fernandez@scripting-base.de>
Reviewed-by: Anja Leichsenring <aleichsenring@ab-softlab.de>
Reviewed-by: Benni Mack <benni@typo3.org>
Reviewed-by: Andreas Fernandez <a.fernandez@scripting-base.de>