[Infer][tests] Adding missing copyright to ActivityLeaks

infer/tests/codetoanalyze/java/infer/ActivityLeaks.java

@@ -1,3 +1,12 @@
+/*
+* Copyright (c) 2015 - present Facebook, Inc.
+* All rights reserved.
+*
+* This source code is licensed under the BSD style license found in the
+* LICENSE file in the root directory of this source tree. An additional grant
+* of patent rights can be found in the PATENTS file in the same directory.
+*/
+
 package codetoanalyze.java.infer;
 
 import android.app.Activity;