Fix crash that happens when we send an object whose type is in a defer

tests/isolate/issue_21398_parent_isolate2_test.dart

Index: tests/isolate/issue_21398_parent_isolate2_test.dart
===================================================================
--- tests/isolate/issue_21398_parent_isolate2_test.dart	(revision 0)
+++ tests/isolate/issue_21398_parent_isolate2_test.dart	(working copy)
@@ -0,0 +1,50 @@
+// Copyright (c) 2015, 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 'dart:isolate';
+import 'dart:async';
+import "package:expect/expect.dart";
+
+import "deferred_loaded_lib.dart" deferred as lib;
+
+// In this test case we send an object created from a defer loaded library

[hausner, 2015/02/13 18:05:49]

So far we've used the term "deferred library" for this.

[siva, 2015/02/13 18:43:41]

Done.

+// that is loaded in the child isolate but not the parent isolate. The
+// parent isolate does not know about the type of this object and throws
+// an unhandled exception.
+funcChild(args) {
+  var replyPort = args[0];
+  // Defer load a library, create an object from that library and send
+  // it over to the parent isolate which has not yet defer loaded that
+  // library.
+  lib.loadLibrary().then((_) {
+    replyPort.send(new lib.FromChildIsolate());
+  });
+}
+
+void helperFunction() {
+  var receivePort = new ReceivePort();
+
+  // Spawn an isolate using spawnFunction.
+  Isolate.spawn(funcChild, [receivePort.sendPort]).then(
+    (isolate) {
+      receivePort.listen(
+        (msg) {
+          // We don't expect to receive any valid messages.
+          Expect.equals(1, 0);

[hausner, 2015/02/13 18:05:49]

Use Expect.fail("should not receive a valid message here");

[siva, 2015/02/13 18:43:41]

Done.

+          receivePort.close();
+        },
+        onError: (e) {
+          // We don't expect to receive any error messages, per spec listen
+          // does not receive an error object.
+          Expect.equals(1, 0);
+          receivePort.close();
+        }
+      );
+    }
+  );
+}
+
+main() {
+  helperFunction(); /// 01: runtime error
+}