[TASK] Upgrade to phpunit 5.3

No notable fancy new features as far as I can see,
just a new minor.

Change-Id: I3363d8a7efa6e774315124536b680a7e84f14bb1
Resolves: #76372
Releases: master
Reviewed-on: https://review.typo3.org/48400


Reviewed-by: Wouter Wolters <typo3@wouterwolters.nl>
Tested-by: Wouter Wolters <typo3@wouterwolters.nl>
Reviewed-by: Mathias Brodala <mbrodala@pagemachine.de>
Reviewed-by: Frank Naegler <frank.naegler@typo3.org>
Tested-by: Frank Naegler <frank.naegler@typo3.org>