dart2js_native tests: Migrate 'native STRING' to JS-calls - part 2/2

tests/compiler/dart2js_native/native_class_fields_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.
 
 import "native_testing.dart";
 
 // Verify that methods are not renamed to clash with native field names
 // that are known from the DOM (like x, y, z).
 @Native("A")
 class A {
   int x;
   int y;
   int z;
   int gettersCalled;
 }
 
-void setup() native r"""
-function getter() {
-  this.gettersCalled++;
-  return 42;
+void setup() {
+  JS('', r"""
+(function(){
+  function getter() {
+    this.gettersCalled++;
+    return 42;
+  }
+
+  function A(){
+    var a = Object.create(
+        { constructor: A },
+        { x: { get: getter, configurable: false, writeable: false },
+          y: { get: getter, configurable: false, writeable: false },
+          z: { get: getter, configurable: false, writeable: false }
+        });
+    a.gettersCalled = 0;
+    return a;
+  }
+
+  makeA = function() { return new A(); };
+  self.nativeConstructor(A);
+})()""");
 }
 
-function A(){
-  var a = Object.create(
-      { constructor: A },
-      { x: { get: getter, configurable: false, writeable: false },
-        y: { get: getter, configurable: false, writeable: false },
-        z: { get: getter, configurable: false, writeable: false }
-      });
-  a.gettersCalled = 0;
-  return a;
-}
-
-makeA = function() { return new A; };
-self.nativeConstructor(A);
-""";
-
 A makeA() native;
 
 class B {
   void a() {}
   void a0() {}
   void a1() {}
   void a2() {}
   void a3() {}
   void a4() {}
   void a5() {}
@@ skipping 113 matching lines @@
   try {
     x.a25();
   } catch (e) {}
   try {
     x.a26();
   } catch (e) {}
   Expect.equals(0, x.gettersCalled);
   Expect.equals(42, x.z);
   Expect.equals(1, x.gettersCalled);
 }