Eliminate old style import from language tests

tests/language/hello_script_lib.dart

 // Copyright (c) 2011, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 // Testing a simple script importing a library.
 // This file contains the library.
 
-#library("HelloScriptLib");
-#source("hello_script_lib_source.dart");
+library HelloScriptLib;
+part "hello_script_lib_source.dart";
 
 class HelloLib {
 
   static doTest() {
     x = 17;
     Expect.equals(17, x++);
     print("Hello from Lib!");
   }
 
 }