isolates refactor: this change introduces 'dart:isolate' as a library. This is a

tests/isolate/src/SerializationTest.dart

Index: tests/isolate/src/SerializationTest.dart
diff --git a/tests/isolate/src/SerializationTest.dart b/tests/isolate/src/SerializationTest.dart
index 0f71af7731220773c44356bc1b43052e9bbf1fb3..e0501069456338d5b8c11fe64febd27d3b54c8a9 100644
--- a/tests/isolate/src/SerializationTest.dart
+++ b/tests/isolate/src/SerializationTest.dart
@@ -9,21 +9,11 @@
 // Serialization test.
 // ---------------------------------------------------------------------------
 #library('SerializationTest');
-#import("dart:coreimpl");
+#import('dart:isolate');
 
 main() {
-  testAllTypes(copy);
-  testAllTypes(serialize);
-}
-
-copy(x) {
-  return new Copier().traverse(x);
-}
-
-serialize(x) {
-  Serializer serializer = new Serializer();
-  Deserializer deserializer = new Deserializer();
-  return deserializer.deserialize(serializer.traverse(x));
+  testAllTypes(TestingOnly.copy);
+  testAllTypes(TestingOnly.serialize);
 }
 
 void testAllTypes(Function f) {