[BUGFIX] Prevent OutOfBoundsException in filelist

Change-Id: I1138487a2bae071d2393a38389ef918b5087d9ea
Resolves: #75370
Releases: master, 7.6
Reviewed-on: https://review.typo3.org/47806


Reviewed-by: Wouter Wolters <typo3@wouterwolters.nl>
Reviewed-by: Christoph Kratz <ckr@rtp.ch>
Tested-by: Christoph Kratz <ckr@rtp.ch>
Reviewed-by: Philipp Gampe <philipp.gampe@typo3.org>
Tested-by: Philipp Gampe <philipp.gampe@typo3.org>