When a user pauses a youtube video and scrolls up high enough to load
new posts, the video either rewinds or restarts depending on the browser.
The problem is solved by patching virtual-dom to handle element prepends
without reordering old elements.
Long-term, Discourse intends to move away from the vdom/widget implementation, so this is intended as a short-term solution. More context at https://meta.discourse.org/t/57692
Co-authored-by: David Taylor <david@taylorhq.com>
* Use QUnit `module` instead of `discourseModule`
* Use QUnit `test` instead of `componentTest`
* Use angle-bracket syntax
* Remove jQuery usage
* Improve assertions (and actually fix some of them)
