More tests updated to optimize code (Part 2).

tests/language/number_identity_test.dart

Index: tests/language/number_identity_test.dart
===================================================================
--- tests/language/number_identity_test.dart	(revision 24922)
+++ tests/language/number_identity_test.dart	(working copy)
@@ -2,11 +2,12 @@
 // 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.
 // Dart test program for testing params.
+// VMOptions=--optimization-counter-threshold=10
 
 import "package:expect/expect.dart";
 
 main() {
-  for (int i = 0; i < 1000; i++) testNumberIdentity();
+  for (int i = 0; i < 20; i++) testNumberIdentity();
 }