Remove dart2js_foreign.

dart/tests/compiler/dart2js_foreign/native_class_is_check1_test.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.
-
-// Test for correct simple is-checks on hidden native classes.
-
-import "package:expect/expect.dart";
-import 'native_metadata.dart';
-
-abstract class I {
-  I read();
-  write(I x);
-}
-
-// Native implementation.
-
-@Native("*A")
-class A implements I  {
-  // The native class accepts only other native instances.
-  @native A read();
-  @native write(A x);
-}
-
-@native makeA();
-
-@Native("""
-// This code is all inside 'setup' and so not accesible from the global scope.
-function A(){}
-A.prototype.read = function() { return this._x; };
-A.prototype.write = function(x) { this._x = x; };
-makeA = function(){return new A};
-""")
-void setup();
-
-class B {}
-
-main() {
-  setup();
-
-  var a1 = makeA();
-  var ob = new Object();
-
-  Expect.isFalse(ob is I);
-  Expect.isFalse(ob is A);
-  Expect.isFalse(ob is B);
-
-  Expect.isTrue(a1 is I);
-  Expect.isTrue(a1 is A);
-  Expect.isTrue(a1 is !B);
-}