Fix GH-19922: gzopen() double free

close GH-19924

ext/zlib/tests/gh19922.phpt

@@ -0,0 +1,12 @@
+--TEST--
+GH-19922 (gzopen double free on debug build and unseekable stream)
+--EXTENSIONS--
+zlib
+--FILE--
+<?php
+var_dump(gzopen("php://output", 14));
+?>
+--EXPECTF--
+
+Warning: gzopen(php://output): could not make seekable - php://output in %s on line %d
+bool(false)