Position: Fix orientation check for scrollbar widths. Fixes #8763 - Position: getScrollInfo() swapped width and height.
Droppable: Changed drop event to loop over a copied array instead of the droppables directly. Fixed #9116 - Droppable: Drop event can cause droppables to remain active if any droppable is created/destroyed in the event handler.
Droppable tests: Cleanup.
Effects: Delegate to core show/hide when the element is already in the correct final state. This forces the element to go through the olddisplay tracking and forces styles on elements even if they're hidden via an ancestor. Fixes #9120 - Effects: .hide() inconsistent with core with a hidden parent.