[TASK] Remove comments that contain v4 or FLOW information

Whether a class or functionality is not available or available
differently in v4 or FLOW is not relevant for TYPO3 CMS.
Remove them.

Occurrences have been searched using:
git grep "TYPO3 4"
git grep " v4"
git grep -l "FLOW" | grep php$

Change-Id: I1e690c2b8eee2af0ade831600ee9a3e1cfe6437a
Releases: master
Resolves: #84126
Reviewed-on: https://review.typo3.org/55994


Tested-by: TYPO3com <no-reply@typo3.com>
Reviewed-by: Mathias Schreiber <mathias.schreiber@typo3.com>
Tested-by: Mathias Schreiber <mathias.schreiber@typo3.com>
Reviewed-by: Benni Mack <benni@typo3.org>
Tested-by: Benni Mack <benni@typo3.org>