Time leakage bug in anime.js when looping animations

Description:
Every time an animation loops the excess time is ignored. This leads to "time leakage" which can accumulate over time or cause issues when high delta times occur for a given tick. This can easily be triggered by giving focus to another tab, which causes browsers to reduce or halt the rAF until the user clicks back again.

Real-world case where this bug causes multiple entities with the same looping animations randomly offset from each other to end up synchronized. https://github.com/3DStreet/3dstreet/issues/364

This is a known bug in anime.js (https://github.com/juliangarnier/anime/issues/561) and is also present in A-Frame's fork. Filing this bug here instead for easier discovery in case other people face this issue.

• A-Frame Version: master
• Platform / Device: any
• Reproducible Code Snippet or URL: https://glitch.com/edit/#!/aspiring-honored-dragonfruit

No source file or test is named. Start by tracing the animation loop and tick timing in A-Frame's animation implementation, then run the linked Glitch reproduction and inspect the anime.js issue for context. Done means looped animations retain excess elapsed time after large frame gaps instead of drifting or synchronizing unexpectedly.