fix super from constructors

tests/language_strong/super_from_constructor_test.dart

+// Copyright (c) 2017, 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";
+
+final results = [];
+
+class Base {
+  m(x) => results.add(x);
+}
+
+class C extends Base {
+  final Iterable _iter;
+
+  C(this._iter) {
+    _iter.map((x) => super.m(x)).toList();
+  }
+}
+
+main() {
+  new C([1, 2, 3]);
+  Expect.listEquals(results, [1, 2, 3]);
+}