Implement dynamic and void as types exported by core library.

pkg/front_end/lib/src/fasta/builder/void_type_builder.dart

Index: pkg/front_end/lib/src/fasta/builder/void_type_builder.dart
diff --git a/pkg/front_end/lib/src/fasta/builder/void_type_builder.dart b/pkg/front_end/lib/src/fasta/builder/void_type_builder.dart
new file mode 100644
index 0000000000000000000000000000000000000000..11d004d56e265405cee34308fe89d5373634098d
--- /dev/null
+++ b/pkg/front_end/lib/src/fasta/builder/void_type_builder.dart
@@ -0,0 +1,13 @@
+// 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.
+
+library fasta.void_type_builder;
+
+import 'builder.dart' show BuiltinTypeBuilder, LibraryBuilder, TypeBuilder;
+
+class VoidTypeBuilder<T extends TypeBuilder, R>
+    extends BuiltinTypeBuilder<T, R> {
+  VoidTypeBuilder(R type, LibraryBuilder compilationUnit, int charOffset)
+      : super("void", type, compilationUnit, charOffset);
+}