Description:
------------
Warnings when opening an non-existing XML file are not being suppressed.

Neither libxml_use_internal_errors(true), nor setting LIBXML_NOERROR | LIBXML_NOWARNING has any effect whatsoever.

The problem seems related to https://bugs.php.net/bug.php?id=64230

Test script:
---------------
<?php

$xml = 'compress.zlib://inexisting_file.xml.gz';

libxml_use_internal_errors(true);

$reader = new XMLReader();
$reader->open($xml, null, LIBXML_NOERROR | LIBXML_NOWARNING);

$reader->read();

print_r(libxml_get_errors());


Expected result:
----------------
No PHP warnings thrown, and an error showing up in print_r


Actual result:
--------------
PHP Warning:  XMLReader::open(compress.zlib://inexisting_file.xml.gz): failed to open stream: operation failed in test.php on line 8
PHP Warning:  XMLReader::open(): Unable to open source data in test.php on line 8
PHP Warning:  XMLReader::read(): Load Data before trying to read in test.php on line 10
Array
(
)