Update utils to new library syntax.

utils/tests/string_encoding/utf16_test.dart

 #!/usr/bin/env dart
 // Copyright (c) 2012, 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.
 
-#library("utf16_tests");
-#import("dunit.dart");
-#import("../../string_encoding/unicode_core.dart");
-#import("../../string_encoding/utf16.dart");
+library utf16_tests;
+import 'dunit.dart';
+import '../../string_encoding/unicode_core.dart';
+import '../../string_encoding/utf16.dart';
 
 void main() {
   TestSuite suite = new TestSuite();
   suite.registerTestClass(new Utf16Tests());
   suite.run();
 }
 
 class Utf16Tests extends TestClass {
   static const String testKoreanCharSubset = """
 가각갂갃간갅갆갇갈갉갊갋갌갍갎갏감갑값갓갔강갖갗갘같갚갛
@@ skipping 107 matching lines @@
     // specify types
     Expect.equals(44032, (new List<int>
         .from(decodeUtf16beAsIterable(testKoreanCharSubsetUtf16beBom)))[0]);
     Expect.equals(44032, (new List<int>
         .from(decodeUtf16leAsIterable(testKoreanCharSubsetUtf16le)))[0]);
     Expect.equals(UNICODE_BOM, (new List<int>
         .from(decodeUtf16beAsIterable(testKoreanCharSubsetUtf16beBom,
               stripBom: false)))[0]);
   }
 }