[TASK] Extract datahandling framework to testing-framework

Ext:core comes with a little testing framework for functional tests,
that is pretty useful for all kind of DataHandler related tests. Those
classes are better located in the testing-framework package to be
available.


Change-Id: I429e801b7318fda3a96acb4f5f63bb75050fb3e3
Resolves: #81154
Releases: master, 8.7
Reviewed-on: https://review.typo3.org/52898


Tested-by: TYPO3com <no-reply@typo3.com>
Reviewed-by: Christian Kuhn <lolli@schwarzbu.ch>
Tested-by: Christian Kuhn <lolli@schwarzbu.ch>