Handle instance fields in compile_from_dill_test

pkg/compiler/lib/src/js_emitter/full_emitter/emitter.dart

 // Copyright (c) 2014, 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.
 
 library dart2js.js_emitter.full_emitter;
 
 import 'dart:collection' show HashMap;
 import 'dart:convert';
 
 import 'package:js_runtime/shared/embedded_names.dart' as embeddedNames;
 import 'package:js_runtime/shared/embedded_names.dart'
     show JsBuiltin, JsGetName;
 
 import '../../../compiler_new.dart';
 import '../../common.dart';
 import '../../compiler.dart' show Compiler;
 import '../../constants/values.dart';
 import '../../common_elements.dart' show CommonElements, ElementEnvironment;
 import '../../elements/resolution_types.dart' show ResolutionDartType;
 import '../../deferred_load.dart' show OutputUnit;
 import '../../elements/elements.dart'
     show
         ClassElement,
         ConstructorBodyElement,
-        Element,
         FieldElement,
-        FunctionSignature,
         LibraryElement,
         MethodElement,
         TypedefElement;
 import '../../elements/entities.dart';
 import '../../elements/entity_utils.dart' as utils;
 import '../../elements/names.dart';
 import '../../hash/sha1.dart' show Hasher;
 import '../../io/code_output.dart';
 import '../../io/location_provider.dart' show LocationCollector;
 import '../../io/source_map_builder.dart' show SourceMapBuilder;
@@ skipping 1936 matching lines @@
     // data.
     mapping["_comment"] = "This mapping shows which compiled `.js` files are "
         "needed for a given deferred library import.";
     mapping.addAll(compiler.deferredLoadTask.computeDeferredMap());
     compiler.outputProvider(
         compiler.options.deferredMapUri.path, '', OutputType.info)
       ..add(const JsonEncoder.withIndent("  ").convert(mapping))
       ..close();
   }
 }