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/base/ecma-helpers-collection.c

@@ -14,6 +14,7 @@
  */
 
 #include "ecma-alloc.h"
+#include "ecma-conversion.h"
 #include "ecma-gc.h"
 #include "ecma-globals.h"
 #include "ecma-helpers.h"
@@ -187,6 +188,61 @@ ecma_collection_append (ecma_collection_t *collection_p, /**< value collection *
   collection_p->item_count += count;
 } /* ecma_collection_append */
 
+/**
+ * Helper function to check if a given collection have duplicated properties or not
+ *
+ * @return true - if there are duplicated properties in the collection
+ *         false - otherwise
+ */
+bool
+ecma_collection_check_duplicated_entries (ecma_collection_t *collection_p) /**< prop name collection */
+{
+  ecma_value_t *buffer_p = collection_p->buffer_p;
+
+  for (uint32_t i = 0; i < collection_p->item_count - 1; i++)
+  {
+    ecma_string_t *current_name_p = ecma_get_prop_name_from_value (buffer_p[i]);
+
+    for (uint32_t j = i + 1; j < collection_p->item_count; j++)
+    {
+      if (ecma_compare_ecma_strings (current_name_p, ecma_get_prop_name_from_value (buffer_p[j])))
+      {
+        return true;
+      }
+    }
+  }
+
+  return false;
+} /* ecma_collection_check_duplicated_entries */
+
+/**
+ * Check the string value existance in the collection.
+ *
+ * Used by:
+ *         - ecma_builtin_json_stringify step 4.b.ii.5
+ *         - ecma_op_object_enumerate
+ *
+ * @return true, if the string is already in the collection.
+ */
+bool
+ecma_collection_has_string_value (ecma_collection_t *collection_p, /**< collection */
+                                  ecma_string_t *string_p) /**< string */
+{
+  ecma_value_t *buffer_p = collection_p->buffer_p;
+
+  for (uint32_t i = 0; i < collection_p->item_count; i++)
+  {
+    ecma_string_t *current_p = ecma_get_string_from_value (buffer_p[i]);
+
+    if (ecma_compare_ecma_strings (current_p, string_p))
+    {
+      return true;
+    }
+  }
+
+  return false;
+} /* ecma_collection_has_string_value */
+
 /**
  * @}
  * @}