Unfurl notifications on AOD=>lockscreen wakeup

During the (AOD<=>LS) transition where dozeAmount is changing,
apply dozeAmount to stack height instead of expansionFraction.

Later this stack height is proportionally distributed to each
notifcation height.

Bug: 213503823
Test: NotificationStackScrollLayoutTest
Test: press power button to wakeup, notifications unfurl
Test: press power button to sleep, notifications furl up

Change-Id: Ia8bcc5763e22ac1418a515f1c69eeed05d3c2104