Allow screen rotation animation when entering AOD

If the device supports AOD2, the device can sleep without
turning off screen. If device is sleeping, DisplayPolicy#isAwake
will be false that causes reject to animate. And if display
orientation is changed, the intermediate state of windows
are shown directly that looks flickering.

Bug: 187149609
Test: Enable "Lock screen" -> "Always show time and info"
      Put launcher in landscape and turn off screen.
      The rotation animation should cover the windows
      which are redrawing for orientating change.
Change-Id: I915026563254bf1c79b0e859f502014a60f9236e