[TASK] Place mixed tests at end of cObj test

To not scatter the system of organising the test methods, create a
section for mixed tests at the very end of the test class.

Resolves: #80552
Releases: master
Change-Id: I56cda89055c79f492527fee6e29ba25426f5f996
Reviewed-on: https://review.typo3.org/52237


Tested-by: TYPO3com <no-reply@typo3.com>
Reviewed-by: Benni Mack <benni@typo3.org>
Tested-by: Benni Mack <benni@typo3.org>