Use for-in loop variable name if possible

tests/compiler/dart2js/kernel/loops_test.dart

Index: tests/compiler/dart2js/kernel/loops_test.dart
diff --git a/tests/compiler/dart2js/kernel/loops_test.dart b/tests/compiler/dart2js/kernel/loops_test.dart
index b257e4b009e922c2b621e38207ad25acf53948af..13a75e759e82f50e6ae6d5a719e7ee500c2c631b 100644
--- a/tests/compiler/dart2js/kernel/loops_test.dart
+++ b/tests/compiler/dart2js/kernel/loops_test.dart
@@ -52,10 +52,8 @@ main() {
   }
   return sum;
 }''';
-    // TODO(het): Check that the code is alpha-equivalent. That is,
-    // the same except for variable names.
     return check(code);
-  }, skip: "The output is the same, with one variable renamed");
+  });
 
   test('for-in loop optimized', () {
     String code = '''