Detect recursion during compilation of const constructors.

tests/language/src/MutuallyRecursiveConstConstructorNegativeTest.dart

Index: tests/language/src/MutuallyRecursiveConstConstructorNegativeTest.dart
===================================================================
--- tests/language/src/MutuallyRecursiveConstConstructorNegativeTest.dart	(revision 0)
+++ tests/language/src/MutuallyRecursiveConstConstructorNegativeTest.dart	(revision 0)
@@ -0,0 +1,19 @@
+// Copyright (c) 2012, 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.
+
+class B {
+  final test = const A(1, b: 2);
+  const B();
+}
+
+class A {
+  final x;
+  final y;
+  const A(a, [b]) : x = a, y = b;
+  final test = const B();
+}
+
+void main() {
+  print(new A(1));
+}