[TASK] Split huge Formhandler test into smaller tests

This patch could stabilize the execution of acceptance tests.

Resolves: #78433
Releases: master
Change-Id: If2598f9f431dce57814a9bf42e384f6222196e2e
Reviewed-on: https://review.typo3.org/50373


Tested-by: TYPO3com <no-reply@typo3.com>
Reviewed-by: Anja Leichsenring <aleichsenring@ab-softlab.de>
Tested-by: Anja Leichsenring <aleichsenring@ab-softlab.de>
Reviewed-by: Christian Kuhn <lolli@schwarzbu.ch>
Tested-by: Christian Kuhn <lolli@schwarzbu.ch>