Verify that user classes/interfaces do not extend/implement any of bool, num,

tests/standalone/src/ProcessInvalidArgumentsTest.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.
 //
 // Process test program to test that invalid arguments throw exceptions.
 
 void testNonStringPath() {
   try {
     Process p = new Process(["true"], []);
     Expect.fail("Did not throw exception");
@@ skipping 13 matching lines @@
 
 void testNonStringArgument() {
   try {
     Process p = new Process("true", ["asdf", 1]);
     Expect.fail("Did not throw exception");
   } catch(var e) {
     Expect.isTrue(e is ProcessException, "Wrong exception type: $e");
   }
 }
 
-class MyString implements String {
-  MyString();
-}
-
-void testMyStringArgument() {
-  Process p = new Process("true", [new MyString()]);
-  try {
-    p.start();
-    Expect.fail("Did not throw exception");
-  } catch(var e) {
-    Expect.isTrue(e is ProcessException, "Wrong exception type: $e");
-  }
-}
-
-void testMyStringPath() {
-  Process p = new Process(new MyString(), ['asdf']);
-  try {
-    p.start();
-    Expect.fail("Did not throw exception");
-  } catch(var e) {
-    Expect.isTrue(e is ProcessException, "Wrong exception type: $e");
-  }
-}
-
 void main() {
   testNonStringPath();
   testNonListArguments();
   testNonStringArgument();
-  testMyStringArgument();
-  testMyStringPath();
 }