Add license to FilePositionMapTest.php

Author: roblourens

tests/FilePositionMapTest.php

@@ -1,4 +1,8 @@
 <?php
+/*---------------------------------------------------------------------------------------------
+ *  Copyright (c) Microsoft Corporation. All rights reserved.
+ *  Licensed under the MIT License. See License.txt in the project root for license information.
+ *--------------------------------------------------------------------------------------------*/
 
 use Microsoft\PhpParser\FilePositionMap;
 use Microsoft\PhpParser\LineCharacterPosition;