[TASK] ext_emconf.php: Fix some inconsistencies

Some 'constraints' related inconsistencies, especially
in test fixture extensions.

Change-Id: I015e34a5519cab166d7941cce35a1661c42b9c5a
Resolves: #83205
Releases: master
Reviewed-on: https://review.typo3.org/54918


Reviewed-by: Stephan Großberndt <stephan@grossberndt.de>
Tested-by: TYPO3com <no-reply@typo3.com>
Reviewed-by: Christian Kuhn <lolli@schwarzbu.ch>
Tested-by: Christian Kuhn <lolli@schwarzbu.ch>