Wrap VariableDeclarations in Blocks as specified by Kernel.

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

Index: pkg/front_end/lib/src/fasta/kernel/body_builder.dart
diff --git a/pkg/front_end/lib/src/fasta/kernel/body_builder.dart b/pkg/front_end/lib/src/fasta/kernel/body_builder.dart
index 09fa92e893162aa71fac8d0afdb4847bcfad65ec..2ad1169e099bd920b9aaac042e44fbe81d229357 100644
--- a/pkg/front_end/lib/src/fasta/kernel/body_builder.dart
+++ b/pkg/front_end/lib/src/fasta/kernel/body_builder.dart
@@ -234,6 +234,8 @@ class BodyBuilder extends ScopeListener<JumpTarget> implements BuilderHelper {
     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;
     }