Rework Object's [[OwnPropertyKeys]] (#4001)

I've removed the ecma_op_object_get_property_names method, and implemented the following ones:
- ecma_op_object_own_property_keys: this is now the internal [[OwnPropertyKeys]] method
- ecma_op_object_enumerate: this is used for the for-in iterator
- ecma_object_sort_property_names: this is used for sorting the property names of an object
- ecma_object_list_lazy_property_names: this is for getting the lazy instantiated properties
- ecma_object_prop_name_is_duplicated: this is for checking if a given property is duplicated in an object

Also the for-in operation with Proxy object works with this patch, #3992 should be closed

JerryScript-DCO-1.0-Signed-off-by: Adam Szilagyi aszilagy@inf.u-szeged.hu

jerry-core/ecma/operations/ecma-string-object.h

@@ -30,9 +30,8 @@ ecma_op_create_string_object (const ecma_value_t *arguments_list_p, uint32_t arg
 
 void
 ecma_op_string_list_lazy_property_names (ecma_object_t *obj_p,
-                                         uint32_t opts,
-                                         ecma_collection_t *main_collection_p,
-                                         ecma_collection_t *non_enum_collection_p);
+                                         ecma_collection_t *prop_names_p,
+                                         ecma_property_counter_t *prop_counter_p);
 
 /**
  * @}