8007698: jtreg test T6306137.java won't compile with ASCII encoding

Reviewed-by: ksrini

test/tools/javac/api/T6306137.java

 /*
- * Copyright (c) 2005, 2006, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2005, 2013, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -25,6 +25,8 @@
  * @test
  * @bug     6306137
  * @summary JSR 199: encoding option doesn't affect standard file manager
+ * @compile -encoding utf-8 T6306137.java
+ * @run main T6306137
  * @author  Peter von der Ahé
  */