Wrap VariableDeclarations in Blocks as specified by Kernel.

pkg/front_end/lib/src/fasta/kernel/body_builder.dart

 // Copyright (c) 2016, 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 fasta.body_builder;
 
 import '../fasta_codes.dart'
     show FastaMessage, codeExpectedButGot, codeExpectedFunctionBody;
 
 import '../parser/parser.dart' show FormalParameterType, optional;
@@ skipping 216 matching lines @@
   }
 
   Statement popStatementIfNotNull(Object value) {
     return value == null ? null : popStatement();
   }
 
   Statement popStatement() {
     var statement = pop();
     if (statement is List) {
       return new Block(new List<Statement>.from(statement));
+    } else if (statement is VariableDeclaration) {
+      return new Block(<Statement>[statement]);
     } else {
       return statement;
     }
   }
 
   void ignore(Unhandled value) {
     pop();
   }
 
   void enterSwitchScope() {
@@ skipping 2723 matching lines @@
   } else if (node is PrefixBuilder) {
     return node.name;
   } else if (node is ThisAccessor) {
     return node.isSuper ? "super" : "this";
   } else if (node is FastaAccessor) {
     return node.plainNameForRead;
   } else {
     return internalError("Unhandled: ${node.runtimeType}");
   }
 }