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

tests/compiler/dart2js_native/subclassing_super_field_2_test.dart

Index: tests/compiler/dart2js_native/subclassing_super_field_2_test.dart
diff --git a/tests/compiler/dart2js_native/subclassing_super_field_2_test.dart b/tests/compiler/dart2js_native/subclassing_super_field_2_test.dart
index c691edfec6846efd2418b812336ccd5479ecddb3..837568a2e0de3a2454102b9b277d6a2ca321ab48 100644
--- a/tests/compiler/dart2js_native/subclassing_super_field_2_test.dart
+++ b/tests/compiler/dart2js_native/subclassing_super_field_2_test.dart
@@ -36,12 +36,15 @@ B makeB() native;
 @Creates('=Object')
 getBPrototype() native;
 
-void setup() native r"""
-function B() { this.foo = 111; }  // N.foo
-makeB = function(){return new B;};
-
-getBPrototype = function(){return B.prototype;};
-""";
+void setup() {
+  JS('', r"""
+(function(){
+  function B() { this.foo = 111; }  // N.foo
+  makeB = function(){return new B()};
+
+  getBPrototype = function(){return B.prototype;};
+})()""");
+}
 
 main() {
   nativeTesting();