Meaning: to unattended use, so no crash dialogs will pop up. In a later
change we can suppress QTest from generating stack traces when this
setting is *not* in server mode (meaning: the OS will take care of the
stack traces).

Change-Id: Idee9311f866228cd35ecb07889f1c19424981221
Reviewed-by: Simon Hausmann <simon.hausmann@qt.io>
Reviewed-by: Jędrzej Nowacki <jedrzej.nowacki@theqtcompany.com>
Reviewed-by: Frederik Gladhorn <frederik.gladhorn@qt.io>