[TASK] Clean up Unit tests in fluid

We had many tests in fluid that are incomplete.
These tests has been incomplete for several years.
Some test has been removed also in TYPO3 fluid.

This patch fix some test by backporting it from
TYPO3 fluid.

The rest of the incomplete tests are also
incomplete in TYPO3 fluid. Maybe we should
ask the Fluid guys.

Fixes: #45331
Releases: 6.1

Change-Id: I38789b98df1dc533b131e54e5eca0cc75b7bc5e0
Reviewed-on: https://review.typo3.org/18171
Reviewed-by: Christian Kuhn
Tested-by: Christian Kuhn