Move dart2jslib parts into separate libraries.

tests/compiler/dart2js/simple_inferrer_no_such_method_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 'package:compiler/src/types/types.dart';
-import 'parser_helper.dart';
 import 'type_mask_test_helper.dart';
 
 const String TEST1 = """
 class A {
   noSuchMethod(im) => 42;
 }
 
 class B extends A {
   foo();
 }
@@ skipping 194 matching lines @@
   var compiler4 = compilerFor(TEST4, uri);
   asyncTest(() => compiler4.runCompiler(uri).then((_) {
     checkReturn(compiler4, 'test1', const TypeMask.nonNullEmpty());
     checkReturn(compiler4, 'test2', compiler4.typesTask.mapType);
     checkReturn(compiler4, 'test3', compiler4.typesTask.mapType);
     checkReturn(compiler4, 'test4', compiler4.typesTask.mapType);
     checkReturn(compiler4, 'test5', compiler4.typesTask.mapType);
     checkReturn(compiler4, 'test6', compiler4.typesTask.mapType);
   }));
 }