Support (de)serialization from command-line

tests/compiler/dart2js/serialization/test_helper.dart

Index: tests/compiler/dart2js/serialization/test_helper.dart
diff --git a/tests/compiler/dart2js/serialization/test_helper.dart b/tests/compiler/dart2js/serialization/test_helper.dart
index fd2cb41e54b52fc37cbc7c90e1056c578cb2142b..496d0e398ae2e4cde4fe6ad745d406f93b6f4c80 100644
--- a/tests/compiler/dart2js/serialization/test_helper.dart
+++ b/tests/compiler/dart2js/serialization/test_helper.dart
@@ -4,23 +4,12 @@
 
 library dart2js.serialization_test_helper;
 
-import 'dart:io';
-import '../memory_compiler.dart';
-import 'package:async_helper/async_helper.dart';
 import 'package:compiler/src/common/resolution.dart';
-import 'package:compiler/src/commandline_options.dart';
-import 'package:compiler/src/constants/constructors.dart';
 import 'package:compiler/src/constants/expressions.dart';
 import 'package:compiler/src/dart_types.dart';
 import 'package:compiler/src/compiler.dart';
-import 'package:compiler/src/diagnostics/invariant.dart';
 import 'package:compiler/src/elements/elements.dart';
-import 'package:compiler/src/elements/visitor.dart';
-import 'package:compiler/src/ordered_typeset.dart';
-import 'package:compiler/src/serialization/element_serialization.dart';
 import 'package:compiler/src/serialization/equivalence.dart';
-import 'package:compiler/src/serialization/json_serializer.dart';
-import 'package:compiler/src/serialization/serialization.dart';
 import 'package:compiler/src/tree/nodes.dart';
 
 /// Strategy for checking equivalence.