Remove "defensive copy" of DatePeriod properties

get_properties() constructs these as fresh objects with no relation
to the internals, there is no need to clone them again. Additionally
the current implementation leaks memory, because the original objects
are never freed (see PR #3121).

ext/date/php_date.c

@@ -5278,21 +5278,14 @@ PHP_METHOD(DatePeriod, __wakeup)
 /* {{{ date_period_read_property */
 static zval *date_period_read_property(zval *object, zval *member, int type, void **cache_slot, zval *rv)
 {
-	zval *zv;
 	if (type != BP_VAR_IS && type != BP_VAR_R) {
 		zend_throw_error(NULL, "Retrieval of DatePeriod properties for modification is unsupported");
 		return &EG(uninitialized_zval);
 	}
 
 	Z_OBJPROP_P(object); /* build properties hash table */
 
-	zv = std_object_handlers.read_property(object, member, type, cache_slot, rv);
-	if (Z_TYPE_P(zv) == IS_OBJECT && Z_OBJ_HANDLER_P(zv, clone_obj)) {
-		/* defensive copy */
-		ZVAL_OBJ(zv, Z_OBJ_HANDLER_P(zv, clone_obj)(zv));
-	}
-
-	return zv;
+	return std_object_handlers.read_property(object, member, type, cache_slot, rv);
 }
 /* }}} */