[scroll-animations-1] Allow `<length-percentage>` in `<keyframe-selector>` when combined with `<timeline-range-name>`

[chromium-helper]

CSSWG added the following resolution(s):

• RESOLVED: Allow `<length-percentage>` in keyframe selectors (with or without `<timeline-range-name>`)

in w3c/csswg-drafts#10000 (comment)

[chromium-helper]

I have filed issues.chromium.org/393810843

That is all that can be done here, closing issue.