[TASK] Avoid vfsStream in FolderTest

The vfsStream setup is not used in the tests.

Resolves: #98935
Related: #97762
Releases: main
Change-Id: I87ec61c1e5aac2bf82e2463e57bc36a81bb211d5
Reviewed-on: https://review.typo3.org/c/Packages/TYPO3.CMS/+/76298


Tested-by: Stefan Bürk <stefan@buerk.tech>
Tested-by: Anja Leichsenring <aleichsenring@ab-softlab.de>
Tested-by: core-ci <typo3@b13.com>
Tested-by: Christian Kuhn <lolli@schwarzbu.ch>
Reviewed-by: Stefan Bürk <stefan@buerk.tech>
Reviewed-by: Anja Leichsenring <aleichsenring@ab-softlab.de>
Reviewed-by: Christian Kuhn <lolli@schwarzbu.ch>