Pretty-print Native AnimatedNode values

Summary:
For debugging, add prettyPrint method to AnimatedNode classes.

Changelog: [Internal]

Reviewed By: shergin

Differential Revision: D22752292

fbshipit-source-id: ce1f08fc4fd97f38629dd82151c6ea762026c7c9

ReactAndroid/src/main/java/com/facebook/react/animated/StyleAnimatedNode.java

@@ -49,4 +49,11 @@ import java.util.Map;
       }
     }
   }
+
+  public String prettyPrint() {
+    return "StyleAnimatedNode["
+        + mTag
+        + "] mPropMapping: "
+        + (mPropMapping != null ? mPropMapping.toString() : "null");
+  }
 }