Update utils to new library syntax.

utils/tests/string_encoding/run_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("string_encoding_run_tests");
-#import("dunit.dart");
-#import("unicode_test.dart", prefix: "u");
-#import("unicode_core_test.dart", prefix: "uc");
-#import("utf16_test.dart", prefix: "utf16");
-#import("utf32_test.dart", prefix: "utf32");
-#import("utf8_test.dart", prefix: "utf8");
+library string_encoding_run_tests;
+import 'dunit.dart';
+import 'unicode_test.dart' as u;
+import 'unicode_core_test.dart' as uc;
+import 'utf16_test.dart' as utf16;
+import 'utf32_test.dart' as utf32;
+import 'utf8_test.dart' as utf8;
 
 void main() {
   TestSuite suite = new TestSuite();
   registerTests(suite);
   suite.run();
 }
 
 void registerTests(TestSuite suite) {
   suite.registerTestClass(new u.UnicodeTests());
   suite.registerTestClass(new uc.UnicodeCoreTests());
   suite.registerTestClass(new utf16.Utf16Tests());
   suite.registerTestClass(new utf32.Utf32Tests());
   suite.registerTestClass(new utf8.Utf8Tests());
 }