ViewGroup: Send events to the child at the event's dispatch location

A mouse event should always be dispatched to the cursor position,
regardless of the location of the pointers in the MotionEvent.

When there are touchpad gestures like a two finger
swipe or a pinch, we promote compatibility with apps by adding fake
pointers that emulate the same behavior on a touchscreen. For example,
two finger swipes turn into a one finger drag, and two finger pinch
emulates a pinch on the screen using two pointers.

The proper way for views to handle touchpad gestures is to look for the
new motion classifications added for touchpad gestures, and dispatch
events at the cursor position for these gestures. However, our API
is incomplete at the moment, becuase apps cannot query the cursor
position.

We can at least fix this in the UiToolkit by dispatching mouse events to
the cursor location.

Bug: 279444161
Test: manual
Test: atest FrameworksCoreTests:ViewGroupTest
Change-Id: I58a9c06b7651ebe97cd03447b083cc9887f863b1