Revert undoing of partial spl_filesystem_object initialization

We're intentionally not initializing spl_filesystem_object.u.dir.entry, as it
will later be initialized, and we don't need to zero the entire buffer anyway.

Author: iluuu1994

ext/spl/spl_directory.c

@@ -187,7 +187,11 @@ static zend_object *spl_filesystem_object_new(zend_class_entry *class_type)
 {
 	spl_filesystem_object *intern;
 
-	intern = ecalloc(1, sizeof(spl_filesystem_object) + zend_object_properties_size(class_type));
+	intern = emalloc(sizeof(spl_filesystem_object) + zend_object_properties_size(class_type));
+	/* Avoid initializing the entirety of spl_filesystem_object.u.dir.entry. */
+	memset(intern, 0,
+		MAX(XtOffsetOf(spl_filesystem_object, u.dir.entry),
+			XtOffsetOf(spl_filesystem_object, u.file.escape) + sizeof(int)));
 	/* intern->type = SPL_FS_INFO; done by set 0 */
 	intern->file_class = spl_ce_SplFileObject;
 	intern->info_class = spl_ce_SplFileInfo;