[FOLLOWUP][TASK] Call explicit render() on icon objects

Change-Id: I267242dd29dc6e773cc6f2f69f24d7b2c98ec8ea
Resolves: #70417
Releases: master
Reviewed-on: http://review.typo3.org/43829


Reviewed-by: Wouter Wolters <typo3@wouterwolters.nl>
Tested-by: Wouter Wolters <typo3@wouterwolters.nl>
Reviewed-by: Frank Nägler <frank.naegler@typo3.org>
Tested-by: Frank Nägler <frank.naegler@typo3.org>