Set DividerView accessibility embedded matrix to surface position

Even though it isn't technically embedded, pretend like it is
embedded into the display. We need to do this because the surface
is moving, but the view content is always drawn at 0,0. For
utilities like View.getBoundsOnScreen to work, this matrix needs
to be updated to offset things properly.

Bug: 151632128
Test: Enter split-screen and dump accessibility nodes if possible.
      UiAutomator-based tests using divider should work again
Change-Id: Icc42e1236f3863dcafbe7f14512082f6f92b76c3