[es6] Reintroduce the instanceof operator in the backends.

src/isolate.h

Index: src/isolate.h
diff --git a/src/isolate.h b/src/isolate.h
index afd27fbed2534a3f4b334d394e81c8acff6b8908..6e6e2efe015b563bd3dde142ad2622bc51f53ab1 100644
--- a/src/isolate.h
+++ b/src/isolate.h
@@ -959,6 +959,7 @@ class Isolate {
 
   bool IsFastArrayConstructorPrototypeChainIntact();
   inline bool IsArraySpeciesLookupChainIntact();
+  inline bool IsHasInstanceLookupChainIntact();
   bool IsIsConcatSpreadableLookupChainIntact();
 
   // On intent to set an element in object, make sure that appropriate
@@ -976,6 +977,7 @@ class Isolate {
     UpdateArrayProtectorOnSetElement(object);
   }
   void InvalidateArraySpeciesProtector();
+  void InvalidateHasInstanceProtector();
   void InvalidateIsConcatSpreadableProtector();
 
   // Returns true if array is the initial array prototype in any native context.