This patch marks some internal cache variables in the
Datahandler as deprecated since their visibility should be
changed from public to protected or even be replaced
by a runtime cache. Since this can't be done before
TYPO3 v9 they are marked as deprecated in TYPO3 v8
as a preparation.

Fixes: #79441
Releases: master
Change-Id: I7d35792fb81e6f16b3b729a3841c1cfda109952f
Reviewed-on: https://review.typo3.org/51411


Reviewed-by: Georg Ringer <georg.ringer@gmail.com>
Tested-by: Georg Ringer <georg.ringer@gmail.com>
Tested-by: TYPO3com <no-reply@typo3.com>
Reviewed-by: Morton Jonuschat <m.jonuschat@mojocode.de>
Tested-by: Morton Jonuschat <m.jonuschat@mojocode.de>