Better constant fold identity checks. (100 bytes saved on swarm, yeah! :))

frog/tests/leg_only/src/ConstantFoldNumberDart2JSTest.dart

Index: frog/tests/leg_only/src/ConstantFoldNumberDart2JSTest.dart
===================================================================
--- frog/tests/leg_only/src/ConstantFoldNumberDart2JSTest.dart	(revision 0)
+++ frog/tests/leg_only/src/ConstantFoldNumberDart2JSTest.dart	(revision 0)
@@ -0,0 +1,13 @@
+// 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.
+// This test is making sure we don't try to constant fold numbers
+// where the semantics differ at compile-time (Dart) and runtime (JS).
+
+foo() => 0.0;
+bar() => 0;
+
+main() {
+  Expect.equals(foo(), bar());
+  Expect.equals(0.0, 0);
+}