[BUGFIX] Improve performance iterating local files

Improve performance iterating local files by avoiding multiple calls to
SplFileInfo.

Releases: master, 8.7
Resolves: #82936
Change-Id: I54b347ad4734d9083b67c7840ff3ab228c07f4bc
Reviewed-on: https://review.typo3.org/54576


Tested-by: TYPO3com <no-reply@typo3.com>
Reviewed-by: Wouter Wolters <typo3@wouterwolters.nl>
Reviewed-by: Stefan Neufeind <typo3.neufeind@speedpartner.de>
Tested-by: Stefan Neufeind <typo3.neufeind@speedpartner.de>
Reviewed-by: Joerg Boesche <typo3@joergboesche.de>
Tested-by: Joerg Boesche <typo3@joergboesche.de>
Reviewed-by: Mathias Brodala <mbrodala@pagemachine.de>
Reviewed-by: Frans Saris <franssaris@gmail.com>
Tested-by: Frans Saris <franssaris@gmail.com>