Add fields to platform library, implement them on runtime dart.

tests/lib/platform/executable_arguments_test.dart

Index: tests/lib/platform/executable_arguments_test.dart
diff --git a/tests/language/issue14014_test.dart b/tests/lib/platform/executable_arguments_test.dart
similarity index 62%
copy from tests/language/issue14014_test.dart
copy to tests/lib/platform/executable_arguments_test.dart
index c887a331219fc6e61a0c94a3ca5831288323e11d..8fbf0327180e1173aadbb8cb9db7a2dd2b74139b 100644
--- a/tests/language/issue14014_test.dart
+++ b/tests/lib/platform/executable_arguments_test.dart
@@ -2,14 +2,10 @@
 // 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.
 
-class A<T> {
-  A(f);
-}
+import "dart:platform" as platform;
 
-class B<T> extends A<T> {
-  B() : super((T param) => 42);
-}
+import "package:unittest/unittest.dart";
 
 main() {
-  var t = new B<int>();
+  expect(platform.executableArguments is List<String>, true);
 }