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 7359c7f86ec00911e735ecc6fc2173a1020202a2..61169c0144ba8e9f59a0c39298754f36ecab4e25 100644
--- a/pkg/compiler/lib/src/js_emitter/full_emitter/emitter.dart
+++ b/pkg/compiler/lib/src/js_emitter/full_emitter/emitter.dart
@@ -365,6 +365,9 @@ 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.