[!!!][BUGFIX] Content Object instances are reused

The ContentObjectRenderer creates instances for each content
object to be rendered, e.g. TEXT, COA, CONTENT, etc. However,
these instances are re-used and therefore we introduced work
arounds since serialization of FLUIDTEMPLATE failed back then.
If dealing with nested record sets using RECORDS or CONTENT,
reusing objects might be tricky since the parent pointer to the
ContentObjectRenderer might be wrong and strange things happen.

This patch removes the pseudo singleton approach since the
objects are not state-less and might lead to unexpected
results in rare cases.

Resolves: #55941
Releases: 6.2
Change-Id: I043a31403c05b87e1591f0e0237effa21bf93c98
Reviewed-on: https://review.typo3.org/27586
Reviewed-by: Markus Klein
Tested-by: Markus Klein
Reviewed-by: Stefan Neufeind
Tested-by: Stefan Neufeind
Reviewed-by: Helmut Hummel
Tested-by: Helmut Hummel