Add corelib tests

test/codegen/corelib/iterable_test.dart

Index: test/codegen/corelib/iterable_test.dart
diff --git a/test/codegen/language/issue10561_test.dart b/test/codegen/corelib/iterable_test.dart
similarity index 58%
copy from test/codegen/language/issue10561_test.dart
copy to test/codegen/corelib/iterable_test.dart
index 24c308c9573e4fbe400d4821e49b9b0ed23e99f4..e7f6299c0ae684e468878327cf541f2ba87e0c7f 100644
--- a/test/codegen/language/issue10561_test.dart
+++ b/test/codegen/corelib/iterable_test.dart
@@ -2,16 +2,17 @@
 // 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.
 
-// Regression test for dart2js that used to miscompile classes
-// extending HashMap, because HashMap is patched.
+// Regression test for dart2js where [List.addAll] was not typed
+// correctly.
 
 import "package:expect/expect.dart";
 
 import 'dart:collection';
 
-class Foo extends Expando {
+class MyIterable extends IterableBase {
+  get iterator => [].iterator;
 }
 
 main() {
-  Expect.isNull(new Foo()[new Object()]);
+  Expect.isTrue(([]..addAll(new MyIterable())).isEmpty);
 }