Support `void` as generic argument.

pkg/compiler/lib/src/js_emitter/full_emitter/emitter.dart

Index: pkg/compiler/lib/src/js_emitter/full_emitter/emitter.dart
diff --git a/pkg/compiler/lib/src/js_emitter/full_emitter/emitter.dart b/pkg/compiler/lib/src/js_emitter/full_emitter/emitter.dart
index 4c0273700a6e570f93c252553d663e54b5f1bdfc..f53f6f4d5a889dd1008fcf17fcbe3db79849e076 100644
--- a/pkg/compiler/lib/src/js_emitter/full_emitter/emitter.dart
+++ b/pkg/compiler/lib/src/js_emitter/full_emitter/emitter.dart
@@ -366,6 +366,9 @@ class Emitter implements js_emitter.Emitter {
       case JsBuiltin.createFunctionTypeRti:
         return backend.rtiEncoder.templateForCreateFunctionType;
 
+      case JsBuiltin.isVoidRti:
+        return backend.rtiEncoder.templateForIsVoidRti;
+
       case JsBuiltin.isSubtype:
         // TODO(floitsch): move this closer to where is-check properties are
         // built.