[TASK] Stabilize a unit test

When executed in random order, a parent directory
may not exist. Take care it's created when needed.

Resolves: #98060
Releases: main
Change-Id: I102aedc8013157527759111d8080a8ee012c7c8e
Reviewed-on: https://review.typo3.org/c/Packages/TYPO3.CMS/+/75338


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