Use Scope::function_kind_ to distinguish arrow function scopes

src/scopes.h

Index: src/scopes.h
diff --git a/src/scopes.h b/src/scopes.h
index 3054f30e2b86d343feb48845915c98220c019d15..723509a78e0048ba422082c3dfc579cc0b8ff15b 100644
--- a/src/scopes.h
+++ b/src/scopes.h
@@ -302,15 +302,15 @@ class Scope: public ZoneObject {
 
   // Specific scope types.
   bool is_eval_scope() const { return scope_type_ == EVAL_SCOPE; }
-  bool is_function_scope() const {
-    return scope_type_ == FUNCTION_SCOPE || scope_type_ == ARROW_SCOPE;
-  }
+  bool is_function_scope() const { return scope_type_ == FUNCTION_SCOPE; }
   bool is_module_scope() const { return scope_type_ == MODULE_SCOPE; }
   bool is_script_scope() const { return scope_type_ == SCRIPT_SCOPE; }
   bool is_catch_scope() const { return scope_type_ == CATCH_SCOPE; }
   bool is_block_scope() const { return scope_type_ == BLOCK_SCOPE; }
   bool is_with_scope() const { return scope_type_ == WITH_SCOPE; }
-  bool is_arrow_scope() const { return scope_type_ == ARROW_SCOPE; }
+  bool is_arrow_scope() const {
+    return is_function_scope() && IsArrowFunction(function_kind_);
+  }
   bool is_declaration_scope() const { return is_declaration_scope_; }
 
   void set_is_declaration_scope() { is_declaration_scope_ = true; }