Const variable declarations accepted in the parser.

tests/language/const_var_test.dart

+// 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.
+// All things regarding constant variables.
+
+#library('const_var');
+
+#import('const_var_helper.dart', prefix: 'foo');
+
+const untypedTopLevel = 1;
+const int typedTopLevel = 2;
+const Map<String,String> genericTopLevel = const <String>{};
+
+main() {
+  const untypedLocal = 3;
+  const int typedLocal = 4;
+  const Map<String,String> genericLocal = const <String>{};
+  const [];
+  const {};
+  const <int>[];
+  const <int>{};
+  const Foo();
+  const Foo<int>();
+  const foo.Foo();
+  const foo.Foo<int>();
+}
+
+class Foo<E> {
+  const Foo();
+}