Fix media overlaying ordering.

Adding alpha support for SurfaceView introduced some state when applying
z-ordering in updateSurface(), so that alpha can be applied to the hole
punch or the layer. This new state was not updated for media overlays,
so fix that.

Bug: 250536276
Bug: 249682951
Test: Applications with overlapping video streams overlap in the correct
order
Test: SurfaceViewTests

Change-Id: I2db37178e9ca800f4e39fd793dc2dc7c43ce5bc3