Only adjust window layers from WindowLayerController

Various animation adjustment logic will directly set mAnimLayer
outside of WindowLayerController. If we end up setting this layer
very high, we can end up moving it above the special windows
collected in WindowLayersController.

Bug: 33702491
Bug: 35396882
Test: bit FrameworksServicesTests:com.android.server.wm.WindowTokenTests
Change-Id: I9850529ecd6f0067bc24421515b39b645885a3ec