2 performance tweaks

0. don't trigger auto-runs during VirtualListView's momentum scroll phase. (bonus)

1. first, only spawn run-loops when absolutely needed
 - don't spawn: if scrollTop is not changing. This drastically helps during pull to refresh/elastic top/bottom scroll. (we where spawning 30-40 during elastic snaps)
 - don't spawn: if no views need recycling (this cuts down the run-loops by at least 2x)

2. apply VirtualListView 3d transforms after recycling, or repositioning ListViewItems