[BUGFIX] Various static calls to non-static functions

Resolves: #56067
Releases: 6.2, 6.1, 6.0
Change-Id: I6d1e19026afde81bec46cec3dff9060fa6042c43
Reviewed-on: https://review.typo3.org/27706
Reviewed-by: Markus Klein
Tested-by: Markus Klein