[BUGFIX] Exclude CDATA from t3lib_parsehtml->XHTML_clean

Due to commit https://review.typo3.org/#/c/30240/ the comments from
javascript is removed and now the javascript is parsed with
config.xhtml_cleaning = all. This patch prevents any CDATA content from
being parsed.

Resolves: #62967
Releases: master, 6.2, 4.5
Change-Id: Ib024c5c8f2b056e47d9222b9767b7a5e6923af8c
Reviewed-on: http://review.typo3.org/34192
Reviewed-by: Oliver Hader <oliver.hader@typo3.org>
Tested-by: Oliver Hader <oliver.hader@typo3.org>