Remove dart2js_foreign.

dart/tests/compiler/dart2js_foreign/foreign_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.
-
-import "package:expect/expect.dart";
-import 'native_metadata.dart';
-
-foreign1(var a, var b) {
-  return JS("num", r"# + #", a, b);
-}
-
-var called = false;
-callOnce() {
-  Expect.isFalse(called);
-  called = true;
-  return 499;
-}
-
-foreign2() {
-  var t = callOnce();
-  return JS("num", r"# + #", t, t);
-}
-
-foreign11(a1, a2, a3, a4, a5, a6, a7, a8, a9, a10, a11) {
-  return JS("num", r"# + # + # + # + # + # + # + # + # + # + #",
-      a1, a2, a3, a4, a5, a6, a7, a8, a9, a10, a11);
-}
-
-void main() {
-  Expect.equals(9, foreign1(4, 5));
-  Expect.equals(998, foreign2());
-  Expect.equals('1234567891011',
-      foreign11('1', '2', '3', '4', '5', '6', '7', '8', '9', '10', '11'));
-}