Revert all the changes to equals operator. Causing buildbot trouble.

tests/language/operator5_test.dart

Index: tests/language/operator5_test.dart
diff --git a/tests/language/operator5_test.dart b/tests/language/operator5_test.dart
index 52c9bcb9894e0c0fc20a29483499c2a5c3edf8e5..87c86fbb8c04163e1256ed1fc1fa47e8f467950c 100644
--- a/tests/language/operator5_test.dart
+++ b/tests/language/operator5_test.dart
@@ -19,6 +19,14 @@ equals(a) {
   }
 }
 
+equalsNull(a) {
+  try {
+    Expect.equals(1, a == null);
+  } catch(TypeError e) {
+    // In checked mode the test doesn't do anything.
+  }
+}
+
 less(a) {
   try {
     Expect.equals(null, a < a);