Optimize the typeof operator.

src/code-factory.h

Index: src/code-factory.h
diff --git a/src/code-factory.h b/src/code-factory.h
index 16ef6d5ffe42260a6b219f2407ee3ef6c223aa71..1007be85ace09a1f44348847c240804782ac9098 100644
--- a/src/code-factory.h
+++ b/src/code-factory.h
@@ -66,6 +66,8 @@ class CodeFactory final {
   static Callable StringAdd(Isolate* isolate, StringAddFlags flags,
                             PretenureFlag pretenure_flag);
 
+  static Callable Typeof(Isolate* isolate);
+
   static Callable FastCloneShallowArray(Isolate* isolate);
   static Callable FastCloneShallowObject(Isolate* isolate, int length);