Change dart2js_foreign suite to use metadata.

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.
 
 interface I {
   I read();
   write(I x);
 }
 
 // Native implementation.
 
-class A implements I native "*A" {
+@native("*A")
+class A implements I  {
   // The native class accepts only other native instances.
-  A read() native;
-  write(A x) native;
+  @native A read();
+  @native write(A x);
 }
 
-makeA() native;
+@native makeA();
 
-void setup() native """
+@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);
 }