[BUGFIX] Make ReferenceIndex caching optional

The runtime caches used in the ReferenceIndex class
added in TYPO3 8.7.2 should not be added by default
but included on a per-runtime basis when extensions
would use the ReferenceIndex. Otherwise this issue
might lead to side-effects.

For master/9.0 the caches are enabled by default.

Relates: #78634
Resolves: #81771
Releases: master, 8.7
Change-Id: If7ca173d93c05658bce5f57c38842555a439d2ea
Reviewed-on: https://review.typo3.org/53384


Reviewed-by: Christian Kuhn <lolli@schwarzbu.ch>
Tested-by: Christian Kuhn <lolli@schwarzbu.ch>
Reviewed-by: Wouter Wolters <typo3@wouterwolters.nl>
Tested-by: TYPO3com <no-reply@typo3.com>
Reviewed-by: Markus Klein <markus.klein@typo3.org>
Tested-by: Markus Klein <markus.klein@typo3.org>