[BUGFIX] Do not disable caching for caches with TransientMemoryBackend

If caching is disabled in the CacheManager, caches using the
TransientMemoryBackend are not adjusted to NullBackend anymore.

This mainly affects the runtime cache, which is memory-based anyways
and should be a "forget after the request"-cache.

This also fixes a PDOException in the page slug update wizard when
using PostgreSQL, as the Install Tool is using the core in "no-cache"
mode. (See entry point of the Install Tool)

Resolves: #91206
Releases: master, 9.5
Change-Id: Id9085bd85bdbf321ef210c75c2bb8aefc6f5f061
Reviewed-on: https://review.typo3.org/c/Packages/TYPO3.CMS/+/64320


Reviewed-by: Markus Klein <markus.klein@typo3.org>
Reviewed-by: Stephan Großberndt <stephan.grossberndt@typo3.org>
Reviewed-by: Benjamin Franzke <bfr@qbus.de>
Tested-by: TYPO3com <noreply@typo3.com>
Tested-by: Stephan Großberndt <stephan.grossberndt@typo3.org>
Tested-by: Markus Klein <markus.klein@typo3.org>
Tested-by: Benjamin Franzke <bfr@qbus.de>