[TASK] Add unit test for ContentObjectRenderer::getFromCache

Resolves: #76717
Releases: master
Change-Id: I016c44eab230cd80cf1404cc552651394e25d15c
Reviewed-on: https://review.typo3.org/48624


Tested-by: Bamboo TYPO3com <info@typo3.com>
Reviewed-by: Daniel Goerz <ervaude@gmail.com>
Tested-by: Daniel Goerz <ervaude@gmail.com>
Tested-by: Michael Oehlhof <typo3@oehlhof.de>
Reviewed-by: Susanne Moog <typo3@susannemoog.de>
Tested-by: Susanne Moog <typo3@susannemoog.de>