[TASK] Add test for categories with multiple tables

Add test for #45332. Remove one relation and check count of collection.

Change-Id: I59871058df97614f7f339c0df241de30e17358b9
Resolves: #50091
Release: master
Reviewed-on: http://review.typo3.org/36477


Reviewed-by: Christian Kuhn <lolli@schwarzbu.ch>
Tested-by: Christian Kuhn <lolli@schwarzbu.ch>
Reviewed-by: Anja Leichsenring <aleichsenring@ab-softlab.de>
Tested-by: Anja Leichsenring <aleichsenring@ab-softlab.de>