Run closed_world2_test using the normal compiler pipeline.

pkg/compiler/lib/src/kernel/native_basic_data.dart

 // Copyright (c) 2017, 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.
 
 // TODO(johnniwinther): Make this a separate library.
 part of dart2js.kernel.element_map;
 
 class KernelAnnotationProcessor implements AnnotationProcessor {
   final KernelToElementMap elementMap;
 
@@ skipping 21 matching lines @@
         }
       }
       if (annotationName != null) {
         nativeBasicDataBuilder.setNativeClassTagInfo(cls, annotationName);
       }
     });
   }
 
   void extractJsInteropAnnotations(
       LibraryEntity library, NativeBasicDataBuilder nativeBasicDataBuilder) {
-    throw new UnimplementedError(
-        'KernelAnnotationProcessor.extractJsInteropAnnotations');
+    // TODO(johnniwinther): Implement this.
   }
 }