Fix typeof optimization for undetectable

src/compiler/typer.cc

Index: src/compiler/typer.cc
diff --git a/src/compiler/typer.cc b/src/compiler/typer.cc
index 5fb20da9a5df17e8f6edf4cb87e1666dfa8aaa75..ca0369c2339152677a3ea3e6d226b8085e57f916 100644
--- a/src/compiler/typer.cc
+++ b/src/compiler/typer.cc
@@ -504,8 +504,8 @@ Type* Typer::Visitor::ToString(Type* type, Typer* t) {
 // Type checks.
 
 Type* Typer::Visitor::ObjectIsCallable(Type* type, Typer* t) {
-  if (type->Is(Type::Callable())) return t->singleton_true_;
-  if (!type->Maybe(Type::Callable())) return t->singleton_false_;
+  if (type->Is(Type::DetectableCallable())) return t->singleton_true_;
+  if (!type->Maybe(Type::DetectableCallable())) return t->singleton_false_;
   return Type::Boolean();
 }