Fixes #646

test fixed.

After a discussion with @kaufi an assertion that caused random 'index out of bounds' exceptions, was commented out with a TODO.

Jenkins:
https://jenkins.catrob.at/job/Catroid-Multi-Job-Custom-Branch/358/

Single device test:
https://jenkins.catrob.at/view/Catroid/job/Catroid-single-UI-device/79/