[TASK] joinTSarrays() is replaced by array_replace_recursive()

\TYPO3\CMS\Frontend\ContentObject\ContentObjectRenderer::joinTSarrays is
replaced by the PHP native array_replace_recursive() (added in PHP 5.3.0)
which does exactly the same and is twice as fast.

Usage of $cObj->joinTSarrays() is deprecated.

Change-Id: I748270a192bccc89927e0d6b82a1f405959b2209
Resolves: #54520
Releases: 6.2
Reviewed-on: https://review.typo3.org/26500
Reviewed-by: Ernesto Baschny
Tested-by: Ernesto Baschny