Improve code for !identical(a, b):

tests/language/identical_test.dart

+// Copyright (c) 2013, 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.
+// Test efficient and correct implementation of !identical(a, b).
+
+notIdenticalTest1(a) {
+  if (!identical("ho", a)) {
+    return 2;
+  } else {
+    return 1;
+  }
+}
+
+notIdenticalTest2(a) {
+  var x = identical("ho", a);
+  if (!x) {
+    Expect.equals(false, x);
+    return x;
+  } else {
+    Expect.equals(true, x);
+    return 1;
+  }
+}
+
+notIdenticalTest3(a) {
+  var x = identical("ho", a);
+  return !x;
+}
+
+main() {
+  for (int i = 0; i < 10000; i++) {
+    Expect.equals(1, notIdenticalTest1("ho"));
+    Expect.equals(1, notIdenticalTest2("ho"));
+    Expect.equals(false, notIdenticalTest3("ho"));
+  }
+}