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

tests/compiler/dart2js_native/jsobject_test.dart

Index: tests/compiler/dart2js_native/jsobject_test.dart
diff --git a/tests/compiler/dart2js_native/jsobject_test.dart b/tests/compiler/dart2js_native/jsobject_test.dart
index 779c6648b38db22cc8bc39f53c6407a563f6be43..dd0ec8ec7dad0c1788502f1280e9a6e6d3bf7f22 100644
--- a/tests/compiler/dart2js_native/jsobject_test.dart
+++ b/tests/compiler/dart2js_native/jsobject_test.dart
@@ -24,7 +24,9 @@ makeA() native;
 makeB() native;
 makeQ() native;
 
-void setup() native r"""
+void setup() {
+  JS('', r"""
+(function(){
 makeA = function(){return {hello: 123};};
 
 function BB(){}
@@ -34,7 +36,8 @@ function QQ(){}
 makeQ = function(){return new QQ();};
 
 self.nativeConstructor(QQ);
-""";
+})()""");
+}
 
 class Is<T> {
   bool check(x) => x is T;