[TASK] Make tests use correct namespaces

Change-Id: I7cc308d3c5c59b1bf8922b6830cf29fb726caa56
Resolves: #51103
Releases: 6.2, 6.1, 6.0
Reviewed-on: https://review.typo3.org/23127
Reviewed-by: Christian Kuhn
Tested-by: Christian Kuhn