Use java.util.Objects instead on internal API

Not needed since java.util.Objects implements all the needed
functionality.

Change-Id: Icd31d49a9801d1705427f028e9ac927d58e7d34c

Conflicts:
	core/java/android/app/ActivityThread.java
	core/java/android/view/DisplayAdjustments.java
	media/java/android/media/MediaRouter.java
	media/lib/java/com/android/media/remotedisplay/RemoteDisplay.java
	packages/DocumentsUI/src/com/android/documentsui/RootsCache.java
	packages/DocumentsUI/src/com/android/documentsui/RootsFragment.java
	services/java/com/android/server/am/ActivityStack.java
	services/java/com/android/server/media/MediaRouterService.java
	services/java/com/android/server/media/RemoteDisplayProviderProxy.java