[TASK] Acceptance testing error handling

Do not generate full back traces but still treat e_warning
as error in acceptance tests.

Change-Id: I56af8bd6a55733b5c2a5286274568dc95b1d2a82
Resolves: #75426
Releases: master
Reviewed-on: https://review.typo3.org/47517


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>