[BUGFIX] Prevent temp file generation in Unit Test

Running Unit Tests creates file /tmp/typo3.log. On Windows systems
this file is stored on the root of the drive. This patch uses the
defined temp folder for storing the file.

Resolves: #76070
Releases: master, 7.6, 6.2
Change-Id: Id77684e41020feb1a1ecff5051a80d2919250bf8
Reviewed-on: https://review.typo3.org/48027


Reviewed-by: Wouter Wolters <typo3@wouterwolters.nl>
Tested-by: Wouter Wolters <typo3@wouterwolters.nl>
Reviewed-by: Andreas Fernandez <typo3@scripting-base.de>
Tested-by: Andreas Fernandez <typo3@scripting-base.de>
Reviewed-by: Susanne Moog <typo3@susannemoog.de>
Tested-by: Susanne Moog <typo3@susannemoog.de>