[BUGFIX] Properly handle translation file detection

The GeneralUtility::llXmlAutoFileName() method will now also correctly
handle paths to files that are not placed within a known directory (ext,
sysext, test etc.) if the call is made with $sameFile = TRUE.

This allows placing language files in storages like fileadmin.

Resolves: #35093
Resolves: #34728
Releases: master, 6.2
Change-Id: Ic5901c3fa98233978abf26db377666dade16f8e6
Reviewed-on: http://review.typo3.org/34285


Reviewed-by: Gernot Ploiner <gp@webprofil.at>
Tested-by: Gernot Ploiner <gp@webprofil.at>
Reviewed-by: Markus Klein <klein.t3@reelworx.at>
Tested-by: Markus Klein <klein.t3@reelworx.at>