Avoid duplicated imports.

dart/tests/compiler/dart2js/type_checker_test.dart

Index: dart/tests/compiler/dart2js/type_checker_test.dart
diff --git a/dart/tests/compiler/dart2js/type_checker_test.dart b/dart/tests/compiler/dart2js/type_checker_test.dart
index 62d231ef9a04d230fe802e942fca3446c580c26b..cb06d743a7c0eaee905db610055ae4600657f269 100644
--- a/dart/tests/compiler/dart2js/type_checker_test.dart
+++ b/dart/tests/compiler/dart2js/type_checker_test.dart
@@ -2,13 +2,12 @@
 // 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.
 
-import "../../../lib/compiler/implementation/dart2jslib.dart" hide SourceString;
-import "../../../lib/compiler/implementation/elements/elements.dart";
-import "../../../lib/compiler/implementation/tree/tree.dart";
-import '../../../lib/compiler/implementation/scanner/scannerlib.dart';
-import "../../../lib/compiler/implementation/util/util.dart";
-import "mock_compiler.dart";
-import "parser_helper.dart";
+import '../../../lib/compiler/implementation/dart2jslib.dart' hide SourceString;
+import '../../../lib/compiler/implementation/elements/elements.dart';
+import '../../../lib/compiler/implementation/tree/tree.dart';
+import '../../../lib/compiler/implementation/util/util.dart';
+import 'mock_compiler.dart';
+import 'parser_helper.dart';
 
 DartType intType;
 DartType boolType;