js/ui: Use Clutter.OffscreenRedirect.ON_IDLE
To bypass offscreening in cases where continuous animation is happening. Offscreening is slower in such cases so this reduces the render time of animations within offscreenable actors.
On an i7-7700 this reduces the render time of boxpointers for example by 25-30%.
Requires mutter!1069 (merged)
Edited by Daniel van Vugt