Implement dynamic and void as types exported by core library.

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

Index: pkg/front_end/lib/src/fasta/kernel/kernel_named_type_builder.dart
diff --git a/pkg/front_end/lib/src/fasta/kernel/kernel_named_type_builder.dart b/pkg/front_end/lib/src/fasta/kernel/kernel_named_type_builder.dart
index 44250a1be5e836369d36b5b41ab244470188aaef..873c3246a15e433f7712c50e29408bcf2dc7f7a3 100644
--- a/pkg/front_end/lib/src/fasta/kernel/kernel_named_type_builder.dart
+++ b/pkg/front_end/lib/src/fasta/kernel/kernel_named_type_builder.dart
@@ -4,8 +4,7 @@
 
 library fasta.kernel_interface_type_builder;
 
-import 'package:kernel/ast.dart'
-    show DartType, DynamicType, Supertype, VoidType;
+import 'package:kernel/ast.dart' show DartType, DynamicType, Supertype;
 
 import '../messages.dart' show warning;
 
@@ -52,15 +51,11 @@ class KernelNamedTypeBuilder
   }
 
   DartType build(LibraryBuilder library) {
-    if (name == "void") return const VoidType();
-    if (name == "dynamic") return const DynamicType();
     if (builder == null) return handleMissingType();
     return builder.buildType(library, arguments);
   }
 
   Supertype buildSupertype(LibraryBuilder library) {
-    if (name == "void") return null;
-    if (name == "dynamic") return null;
     if (builder == null) return handleMissingSupertype();
     if (builder is KernelClassBuilder) {
       KernelClassBuilder builder = this.builder;