Flag methods as not being valid compile time constants

tests/language/src/ConstInit7NegativeTest.dart

+// Copyright (c) 2011, 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.
+// Check that a method reference is not an acceptable compile time constant
+
+
+topMethod() { }
+
+class ConstInit7NegativeTest {
+  classMethod([var x = 
+    topMethod // Error: not a compile time const.
+  ]) {}
+}
+
+main() {
+ new ConstInit7NegativeTest();
+}