[BUGFIX] use gmmktime in checkConditionMatcherForDateFunction unit test

The arguments are now treated as parts of a UTC date/time and
prevents different results depending on the system date.timezone
settings.

Releases: master
Resolves: #86128
Change-Id: Ieb336ea43eb246ec0e0c5a7db8194c03a0801f83
Reviewed-on: https://review.typo3.org/58165


Reviewed-by: Susanne Moog <susanne.moog@typo3.org>
Reviewed-by: Andreas Fernandez <a.fernandez@scripting-base.de>
Tested-by: TYPO3com <no-reply@typo3.com>
Tested-by: Susanne Moog <susanne.moog@typo3.org>
Reviewed-by: Georg Ringer <georg.ringer@gmail.com>
Tested-by: Georg Ringer <georg.ringer@gmail.com>