[TASK] Fatal error in database connect install step

Patch df239a6d599 renamed bootstrap method setCoreCacheToNullBackend
to disableCoreAndClassesCache but missed a usage in installer.

Change-Id: Ie4939384a7c476c489d8734ecd7badf5f0dcebdc
Resolves: #56605
Related: #56583
Releases: 6.2
Reviewed-on: https://review.typo3.org/28102
Reviewed-by: Christian Kuhn
Tested-by: Christian Kuhn