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

tests/compiler/dart2js_native/subclassing_constructor_1_test.dart

 // Copyright (c) 2013, 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";
 import 'dart:_js_helper' show setNativeSubclassDispatchRecord;
 import 'dart:_interceptors'
     show findInterceptorForType, findConstructorForNativeSubclassType;
 
 // Test that subclasses of native classes can be initialized by calling the
@@ skipping 42 matching lines @@
   B.three([x]) : super.three(205, x);
 
   get increment => 20;
 }
 
 makeB() native;
 
 @Creates('=Object')
 getBPrototype() native;
 
-void setup() native r"""
-function B() { this.a2 = 102; }
+void setup() {
+  JS('', r"""
+(function(){
+  function B() { this.a2 = 102; }
 
-makeB = function(){return new B;};
+  makeB = function(){return new B()};
 
-getBPrototype = function(){return B.prototype;};
-""";
+  getBPrototype = function(){return B.prototype;};
+})()""");
+}
 
 test_one() {
   trace = [];
   var constructor = findConstructorForNativeSubclassType(B, 'one');
   Expect.isNotNull(constructor);
   Expect.isNull(findConstructorForNativeSubclassType(B, 'Missing'));
 
   var b = makeB();
   Expect.isTrue(b is B);
   // Call constructor to initialize native object.
@@ skipping 85 matching lines @@
     return message;
   };
 
   setNativeSubclassDispatchRecord(getBPrototype(), findInterceptorForType(B));
 
   test_one();
   test_two();
   test_three();
   test_new();
 }