Add additional runtime type checks.

tests/language/src/TypeDartcTest.dart

 // 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.
 // VMOptions=--enable_type_checks --enable_asserts
 //
 // Dart test program testing type checks.
 
 class TypeTest {
   static test() {
     int result = 0;
@@ skipping 476 matching lines @@
 
   static testMain() {
     Expect.equals(1, test());
     Expect.equals(1, testSideEffect());
     Expect.equals(1, testArgument());
     Expect.equals(1, testReturn());
     Expect.equals(1, testField());
     Expect.equals(1, testAnyFunction());
     //Expect.equals(1, testVoidFunction()); - Function type checking issue
     //Expect.equals(1, testFunctionNum());  - Function type checking issue
-    //Expect.equals(9, testBoolCheck());    - Boolean checking on conditions is not done
+    Expect.equals(9, testBoolCheck());
     //Expect.equals(1, testFactory());      - Not doing a test on factories
     Expect.equals(8, testListAssigment());
   }
 }
 
 
 class C {
   factory C() {
     return 1;  // Implicit result type is 'C', not int.
   }
 }
 
 
 main() {
   TypeTest.testMain();
 }