MQE-431: Automatically check for copyright at the top of every framework file

- Adding copyright to a file which made it to sprint-develop before this task.

Author: tomreece

dev/tests/phpunit.xml

@@ -1,3 +1,10 @@
+<!--
+ /**
+  * Copyright © Magento, Inc. All rights reserved.
+  * See COPYING.txt for license details.
+  */
+-->
+
 <phpunit
     xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
     xsi:noNamespaceSchemaLocation="https://schema.phpunit.de/6.3/phpunit.xsd"