[BUGFIX] Avoid raising a warning in SimpleLockStrategyTest

The touch command raises a PHP WARNING if the test file can not be
created, but the next line would already skip the test if this
happens.
So the warning is useless and gets silenced.

Resolves: #88255
Releases: master, 9.5, 8.7
Change-Id: Id9685b6e7da8665609fa7df7f25867ab4d19a6a9
Reviewed-on: https://review.typo3.org/c/Packages/TYPO3.CMS/+/60640


Tested-by: TYPO3com <noreply@typo3.com>
Tested-by: Markus Klein <markus.klein@typo3.org>
Tested-by: Andreas Fernandez <a.fernandez@scripting-base.de>
Reviewed-by: Markus Klein <markus.klein@typo3.org>
Reviewed-by: Andreas Fernandez <a.fernandez@scripting-base.de>