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

tests/compiler/dart2js_native/event_loop_test.dart

Index: tests/compiler/dart2js_native/event_loop_test.dart
diff --git a/tests/compiler/dart2js_native/event_loop_test.dart b/tests/compiler/dart2js_native/event_loop_test.dart
index b080373d63ad0e30f02448d3593a0c63c131c6c6..e69d542c32ff8c3daf8f06dd3999c2efa5d43b5c 100644
--- a/tests/compiler/dart2js_native/event_loop_test.dart
+++ b/tests/compiler/dart2js_native/event_loop_test.dart
@@ -15,12 +15,15 @@ class A {
 
 makeA() native;
 
-void setup() native r"""
+void setup() {
+  JS('', r"""
+(function(){
 function A() {}
 A.prototype.foo = function(f) { return f(); };
-makeA = function() { return new A; };
+makeA = function() { return new A(); };
 self.nativeConstructor(A);
-""";
+})()""");
+}
 
 main() {
   nativeTesting();