Work around argument corruption bug in XMLReader::open
Use a static call to XMLReader::open() in PHP 8.0.0+.
Remove the check for LIBXML_PARSEHUGE since it is always available in
PHP 7.4+. The #ifdef was removed.
Bug: T330464
Change-Id: I39f050c5d4e461923a84ebb8b3b1d92c021d2e7a
(cherry picked from commit 7aeadbf81bba17051d8d9b52969d4ff398c6b0dd)