Throw a type error in production mode when the type of the type test is not

tests/language/src/IsNotClass3NegativeTest.dart

Index: tests/language/src/IsNotClass3NegativeTest.dart
===================================================================
--- tests/language/src/IsNotClass3NegativeTest.dart	(revision 6753)
+++ tests/language/src/IsNotClass3NegativeTest.dart	(working copy)
@@ -1,23 +0,0 @@
-// Copyright (c) 2011, 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.
-// Dart test program for catch that we expect a class after an 'is'.
-
-class A {
-  const A();
-}
-
-class IsNotClass3NegativeTest {
-  static testMain() {
-    var a = new A();
-
-    if (a is B) {
-      return 0;
-    }
-    return 0;
-  }
-}
-
-main() {
-  IsNotClass3NegativeTest.testMain();
-}