[BUGFIX] Respect rootline order for getPagesTSconfig()

The method TypoScriptFrontendController::getPagesTSconfig() now
respects overrides via TSconfig and now returns the actual
configuration valid for the current page.

Change-Id: I1288086b51f8c5b3d96853fb7669a9cbb11ecaef
Resolves: #22710
Releases: master
Reviewed-on: http://review.typo3.org/41798


Reviewed-by: Ralf Merz <info@merzilla.de>
Reviewed-by: Markus Klein <markus.klein@typo3.org>
Tested-by: Markus Klein <markus.klein@typo3.org>
Reviewed-by: Stefan Neufeind <typo3.neufeind@speedpartner.de>
Tested-by: Stefan Neufeind <typo3.neufeind@speedpartner.de>