TYPO3 Core

All currently existing functional tests dealing with ManyToMany Relations base on table 'sys_category', which leads to
- doubled up, but not completely covered test for the TCA category type, which bases on the same table
- missing test scenarios for other MM relations, whose TCA configuration differs from category type.

To free the broader purpose section of ManyToMany functional tests for those missing scenarios, the section for TCA type category is synchronized with the existing tests. So the category scenario remains complete, while we can later on remove the category related tests from ManyToMany.