Change dart2js_foreign suite to use metadata.

dart/tests/compiler/dart2js_foreign/native_call_arity3_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.
 
 // Test similar to NativeCallArity1FrogTest, but with default values to
 // parameters set to null. These parameters should be treated as if they
 // do not have a default value for the native methods.
 
-class A native "*A" {
-  int foo(int x) native;
+@native("*A")
+class A  {
+  @native int foo(int x);
 }
 
-class B native "*B" {
-  int foo([x = null, y, z = null]) native;
+@native("*B")
+class B  {
+  @native int foo([x = null, y, z = null]);
 }
 
 // TODO(sra): Add a case where the parameters have default values.  Wait until
 // dart:dom_deprecated / dart:html need non-null default values.
 
-A makeA() native { return new A(); }
-B makeB() native { return new B(); }
+@native A makeA() { return new A(); }
+@native B makeB() { return new B(); }
 
-void setup() native """
+@native("""
 function A() {}
 A.prototype.foo = function () { return arguments.length; };
 
 function B() {}
 B.prototype.foo = function () { return arguments.length; };
 
 makeA = function(){return new A;};
 makeB = function(){return new B;};
-""";
+""")
+void setup();
 
 
 testDynamicContext() {
   var things = [makeA(), makeB()];
   var a = things[0];
   var b = things[1];
 
   Expect.throws(() => a.foo());
   Expect.equals(1, a.foo(10));
   Expect.throws(() => a.foo(10, 20));
@@ skipping 28 matching lines @@
   Expect.equals(2, b.foo(y: 20));
   Expect.equals(3, b.foo(z: 30));
   Expect.throws(() => b.foo(10, 20, 30, 40));
 }
 
 main() {
   setup();
   testDynamicContext();
   testStaticContext();
 }