Remove taskbar tooltip hover delay.

Fix issue when setting fullscreen drag layer causes hover exit/enter events.

Update ArrowTipView paddings to match spec.

Update ArrowTipView to check on each time it is shown if it should point up or down, not only the first time.

Fix: 295851126
Fix: 295315397
Test: TaskbarHoverToolTipControllerTest
Change-Id: I314c65cb9fce3fb8d6002d8917bd5c97301d9dbc