Remove superfluous update of parent when setting currentTime.
Remove superfluous update of parent when setting currentTime.

The parent is not affected by the child's local time, so this update is not
required.

web-animations/web-animations-js-legacy,beni55/web-animations-js-legacy,birtles/web-animations-js,dstockwell/web-animations-js,dstockwell/web-animations-js,birtles/web-animations-js,web-animations/web-animations-js-legacy,beni55/web-animations-js-legacy,web-animations/web-animations-js-legacy,beni55/web-animations-js-legacy,beni55/web-animations-js-legacy,birtles/web-animations-js