Change dart2js_foreign suite to use metadata.

dart/tests/compiler/dart2js_foreign/native_field_rename_2_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.
 
 // A native method prevents other members from having that name, including
 // fields.  However, native fields keep their name.  The implication: a getter
 // for the field must be based on the field's name, not the field's jsname.
 
 interface I {
   int key;
 }
 
-class A implements I native "*A" {
+@native("*A")
+class A implements I  {
   int key;                    //  jsname is 'key'
   int getKey() => key;
 }
 
 class B implements I {
   int key;                    //  jsname is not 'key'
   B([this.key = 222]);
   int getKey() => key;
 }
 
-class X native "*X" {
-  int native_key_method() native 'key';
+@native("*X")
+class X  {
+  @native('key') int native_key_method();
   // This should cause B.key to be renamed, but not A.key.
-  int key() native 'key';
+  @native('key') int key();
 }
 
-A makeA() native;
-X makeX() native;
+@native A makeA();
+@native X makeX();
 
 
-void setup() native """
+@native("""
 // This code is all inside 'setup' and so not accesible from the global scope.
 function A(){ this.key = 111; }
 A.prototype.getKey = function(){return this.key;};
 
 function X(){}
 X.prototype.key = function(){return 666;};
 
 makeA = function(){return new A};
 makeX = function(){return new X};
-""";
+""")
+void setup();
 
 testDynamic() {
   var things = [makeA(), new B(), makeX()];
   var a = things[0];
   var b = things[1];
   var x = things[2];
 
   Expect.equals(111, a.key);
   Expect.equals(222, b.key);
   Expect.equals(111, a.getKey());
@@ skipping 29 matching lines @@
   Expect.equals(222, b.getKey());
 }
 
 main() {
   setup();
 
   testTyped();
   testPartial();
   testDynamic();
 }