[CLEANUP] #5209 Use makeInstance in the unit tests only for singletons

Change-Id: I31cac3769badf251bae79e75e56e1a61a40eab8d
Reviewed-on: http://review.typo3.org/35649
Reviewed-by: Oliver Klee <typo3-coding@oliverklee.de>
Tested-by: Oliver Klee <typo3-coding@oliverklee.de>