Migrate test block 113 to Dart 2.0.

tests/language_strong/generic2_test.dart

-// Copyright (c) 2013, 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.
-
-// Test is-tests with type variables.
-
-import "package:expect/expect.dart";
-
-class A<T> {
-  foo(o) => o is T;
-}
-
-class B {}
-
-class C extends A<int> {}
-
-main() {
-  Expect.isTrue(new A<Object>().foo(new B()));
-  Expect.isTrue(new A<Object>().foo(1));
-  Expect.isFalse(new A<int>().foo(new Object()));
-  Expect.isFalse(new A<int>().foo('hest'));
-  Expect.isTrue(new A<B>().foo(new B()));
-  Expect.isFalse(new A<B>().foo(new Object()));
-  Expect.isFalse(new A<B>().foo(1));
-  Expect.isTrue(new C().foo(1));
-  Expect.isFalse(new C().foo(new Object()));
-  Expect.isFalse(new C().foo('hest'));
-  Expect.isTrue(new A<List<int>>().foo(new List<int>()));
-  Expect.isFalse(new A<List<int>>().foo(new List<String>()));
-}