[BUGFIX] Invalid cache backend option "compression" for NullBackend

If a Typo3DatabaseBackend is changed to NullBackend, the compression flag
may be set and should be part of the NullBackend interface.

Change-Id: Id70dc582ddbe87eb8388dd79963364c23900e417
Fixes: #49585
Releases: 6.2, 6.1, 6.0
Reviewed-on: https://review.typo3.org/21801
Reviewed-by: Anja Leichsenring
Tested-by: Anja Leichsenring