Remove dart2js_foreign.

dart/tests/compiler/dart2js_foreign/native_null_closure_test.dart

-// Copyright (c) 2012, 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';
-
-typedef void MyFunctionType();
-
-@Native("*A")
-class A {
-  @native setClosure(MyFunctionType f);
-  @native check(MyFunctionType f);
-  @native invoke();
-}
-
-@native makeA() { return new A(); }
-
-@Native("""
-function A() {}
-A.prototype.setClosure = function(f) { this.f = f; };
-A.prototype.check = function(f) { return this.f === f; };
-A.prototype.invoke = function() { return this.f(); };
-makeA = function(){return new A;};
-""")
-void setup();
-
-
-main() {
-  setup();
-  A a = makeA();
-  a.setClosure(null);
-  Expect.isTrue(a.check(null));
-  bool caughtException = false;
-  try {
-    a.invoke();
-  } on Exception catch (e) {
-    caughtException = true;
-  }
-  Expect.isTrue(caughtException);
-}