Transition to fullscreen based on position of motion event

The position of a task is calculated by subtracting the
position of the motion event relative to the task from the motion event
relative to the display. When a task is dragged quickly to the top to
transition into fullscreen, the difference becomes a large number that
is greater than the status bar height, so, the task does not transition
into fullscreen. This change uses the raw y of the motion event to check
if the task should transition to fullscreen.

Bug: 281907587
Test: Quickly drag task to the top of the screen to make sure it
transitions to freeform.

Change-Id: I3bf58b9e60e357a3d2349640639b711084e42f00