Summary:
Resetting timeline while animating a window causes some visual "glitches",
see videos below. Even though we can't use `QTimer::toggleDirection`,
that's safe to delete code which resets timeline because `prePaintScreen`
figures out correct direction of the timeline.
Before
{F5809835, layout=center, size=full}
After
{F5809850, layout=center, size=full}
Test Plan:
* Set duration to 5000
* Furiously click an icon in the task manager
Reviewers: #kwin, davidedmundson
Reviewed By: davidedmundson
Subscribers: kwin
Tags: #kwin
Differential Revision: https://phabricator.kde.org/D12253
913f92ae9a