Add onChildEndedNativeGesture to JSTouchDispatcher and ReactRootView to handle child gesture finishes event

Summary:
Changelog:
[Android][Added] Adding new API `onChildEndedNativeGesture` to the RootView interface to let its implementations notify the JS side that a child gesture is ended.

Reviewed By: javache

Differential Revision: D32228745

fbshipit-source-id: ad1f26546dd60f9c5a569b0bc3ad5020a01b90cc

ReactAndroid/src/main/java/com/facebook/react/uimanager/RootView.java

@@ -22,5 +22,11 @@ public interface RootView {
   /** @deprecated */
   void onChildStartedNativeGesture(MotionEvent ev);
 
+  /**
+   * Called when a child ends a native gesture. Should be called from the child's onTouchIntercepted
+   * implementation.
+   */
+  void onChildEndedNativeGesture(View childView, MotionEvent ev);
+
   void handleException(Throwable t);
 }