Replace ICStub for array.length with hydrogen stub

src/hydrogen.h

Index: src/hydrogen.h
diff --git a/src/hydrogen.h b/src/hydrogen.h
index 7f5326bcb5422053548ae3e086cf646b7c48ffa2..5a2df656caee3c3e0fb63ee0aaf9753d01e90b44 100644
--- a/src/hydrogen.h
+++ b/src/hydrogen.h
@@ -921,6 +921,8 @@ class HGraphBuilder {
       bool is_store,
       Representation checked_index_representation = Representation::None());
 
+  HInstruction* BuildFastArrayLengthLoad(HValue* object, HValue* typecheck);
+
   HInstruction* BuildStoreMap(HValue* object, HValue* map, BailoutId id);
   HInstruction* BuildStoreMap(HValue* object, Handle<Map> map, BailoutId id);
 
@@ -1311,6 +1313,10 @@ class HOptimizedGraphBuilder: public HGraphBuilder, public AstVisitor {
                                        HValue* object,
                                        SmallMapList* types,
                                        Handle<String> name);
+  bool HandlePolymorphicArrayLengthLoad(Property* expr,
+                                        HValue* object,
+                                        SmallMapList* types,
+                                        Handle<String> name);
   void HandlePolymorphicStoreNamedField(Assignment* expr,
                                         HValue* object,
                                         HValue* value,
@@ -1383,6 +1389,8 @@ class HOptimizedGraphBuilder: public HGraphBuilder, public AstVisitor {
                                           Property* expr,
                                           Handle<Map> map);
 
+  void AddCheckMap(HValue* object, Handle<Map> map);
+
   void AddCheckMapsWithTransitions(HValue* object,
                                    Handle<Map> map);