Timeline animations with duration = 0 not working

[davidmondok]

This might be a duplicate of #228 but since that issue was posted back in 2017 and we're already at version 3 I thought I submit a new issue.

When I set the duration of a timeline animation to 0 I would expect the animation to be instant. This is not the case though. Instead the targeted elements instantly receives the properties defined in the last timeline animation where the duration was set to 0 (properties from all animations before that step are ignored regardless of their durations; the timing is kind of still respected though weirdly). You can see the behaviour I'm talking about in the linked codepen, it's the second animation.

I created https://codepen.io/damoondog/pen/mvgMdN to illustrate the issue.