Const constructor must have const super initializer

tests/language/const_constructor_super_test.dart

+// Copyright (c) 2013, 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";
+
+class A {
+  final a;
+  A(this.a);  // Not const.
+  const A.five() : a = 5;
+}
+
+class B extends A {
+  final b;
+  B(x) : b = x + 1, super(x);
+
+  // Const constructor cannot call non-const super constructor.
+  const B.zerofive() : b = 0, super(5);  /// 01: compile-time error
+}
+
+class C extends A {
+  C() : super(0);
+  // Implicit call to non-const constructor A(x).
+  const C.named(x);  /// 02: compile-time error
+}
+
+main() {
+  var b = new B.zerofive();  /// 01: continued
+  var b1 = new B(0);
+  var c = new C.named("");  /// 02: continued
+}