Strong mode cleaning of many dart2js tests.

tests/compiler/dart2js/analyze_dart2js_helpers_test.dart

 // Copyright (c) 2015, 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.analyze_helpers.test;
 
 import 'dart:io';
 
 import 'package:async_helper/async_helper.dart';
 import 'package:compiler/compiler_new.dart' show Diagnostic;
@@ skipping 43 matching lines @@
         if (verbose) {
           print('---- analyzing $file ----');
         }
         LibraryElement library = await compiler.analyzeUri(file);
         if (library != null) {
           if (library.libraryName == 'dart2js.helpers') {
             helperLibrary = library;
           }
           library.forEachLocalMember((Element element) {
             if (element is ClassElement) {
-              element.forEachLocalMember((AstElement member) {
+              element.forEachLocalMember((_member) {
+                AstElement member = _member;
                 analyzer.analyze(member.resolvedAst);
               });
             } else if (element is MemberElement) {
               analyzer.analyze(element.resolvedAst);
             }
           });
         }
       }
     }
     Expect.isNotNull(helperLibrary, 'Helper library not found');
@@ skipping 133 matching lines @@
     apply(arguments);
   }
 
   @override
   void visitConstConstructorInvoke(
       NewExpression node, ConstructedConstantExpression constant, _) {
     ConstructorElement constructor = constant.target;
     checkAccess(node, constructor);
   }
 }