[TASK] Replace static variable with class variable in FileInfo

By removing the graphicFunctions object from global scope, unit
tests are easier to add in this area.

Change-Id: I8ddf4e0282d42325ecb03c98bede91bf6e1b636c
Resolves: #84933
Releases: master, 8.7
Reviewed-on: https://review.typo3.org/56867


Reviewed-by: Anja Leichsenring <aleichsenring@ab-softlab.de>
Tested-by: Anja Leichsenring <aleichsenring@ab-softlab.de>
Reviewed-by: Christian Kuhn <lolli@schwarzbu.ch>
Tested-by: Christian Kuhn <lolli@schwarzbu.ch>
Tested-by: TYPO3com <no-reply@typo3.com>
Reviewed-by: Frank Naegler <frank.naegler@typo3.org>
Tested-by: Frank Naegler <frank.naegler@typo3.org>