Realign start time if finite timeline and auto-rewind is true

[johannesodland]

Another two tests where the spec and the wpt does not align.

The wpt tests suggests that the start time should be auto aligned when playing an animation, as long as the finite timeline and auto-rewind flags are true. Chrome currently passes these tests.

I think it's best to follow the test and Chromes implementation here, and adjust later if necessary?

[johannesodland]

What is the best approach here, when the spec, wpt tests and Chrome implementation differ?

Should we raise an issue in the csswg-issues repo? Or is it just that the tests and implementation is behind the spec?