[BUGFIX] Backport null checks to Core QueryGenerator

This file was removed in v12 and only the version in
TYPO3\CMS\Lowlevel\Database\QueryGenerator
was updated with fixes.

This patch backports all the checks to the v11
TYPO3\CMS\Core\Database\QueryGenerator

Resolves: #98536
Releases: 11.5
Change-Id: I7aabc6e5b31529c15fd50b390c346b1ec7caf71d
Reviewed-on: https://review.typo3.org/c/Packages/TYPO3.CMS/+/78139


Reviewed-by: Andreas Fernandez <a.fernandez@scripting-base.de>
Tested-by: Christian Kuhn <lolli@schwarzbu.ch>
Tested-by: core-ci <typo3@b13.com>
Reviewed-by: Ralph Brugger <typo3bugs@public.linkpool.de>
Reviewed-by: Oliver Klee <typo3-coding@oliverklee.de>
Tested-by: Andreas Fernandez <a.fernandez@scripting-base.de>
Reviewed-by: Christian Kuhn <lolli@schwarzbu.ch>