dart2dart: Support for all constants in new backend.

tests/language/reify_typevar_test.dart

 // Copyright (c) 2014, 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";
 
-// Regression test for Issue 16407.
-
-void main() {
-  foo(null, true);
-  foo('x', false);
+class Foo<T> {
+    reify() {
+        return T;
+    }
 }
 
-var foo = (x, result) {
-  Expect.equals(result, x is Null, '$x is Null');
-};
+main() {
+    Expect.equals(int, new Foo<int>().reify());
+    Expect.equals(Foo, new Foo().runtimeType);
+}