Revert "Move dart2jslib parts into separate libraries."

tests/compiler/dart2js/closure_tracer_test.dart

 // Copyright (c) 2013, 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.
 
 import 'package:expect/expect.dart';
 import "package:async_helper/async_helper.dart";
 
 import 'compiler_helper.dart';
+import 'parser_helper.dart';
 import 'type_mask_test_helper.dart';
 
 const String TEST = '''
 testFunctionStatement() {
   var res;
   closure(a) => res = a;
   closure(42);
   return res;
 }
 
@@ skipping 152 matching lines @@
     checkType('testStoredInListOfList', typesTask.uint31Type);
     checkType('testStoredInListOfListUsingInsert', typesTask.uint31Type);
     checkType('testStoredInListOfListUsingAdd', typesTask.uint31Type);
     checkType('testPassedInParameter', typesTask.uint31Type);
     checkType('testStaticClosure1', typesTask.uint31Type);
     checkType('testStaticClosure2', typesTask.numType);
     checkType('testStaticClosure3', typesTask.uint31Type);
     checkType('testStaticClosure4', typesTask.numType);
   }));
 }