Description:
------------
Previously when an implementation of php_user_filter::filter() returned PSFS_ERR_FATAL, stream_copy_to_stream() was returning false we now get 0.

https://3v4l.org/dD9ZH


This seems to have been introduced by https://github.com/php/php-src/commit/d59aac58b3e7da7ad01a194fe9840d89725ea229

Is this behavior change expected?

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

class MyFilter extends php_user_filter {
    public function filter($in, $out, &$consumed, $closing)
    {
        stream_bucket_make_writeable($in);
        return PSFS_ERR_FATAL;
    }

}

stream_filter_register('filtername', MyFilter::class);

$source_resource = fopen('php://memory', 'rb+');
fwrite($source_resource, 'Test data');
rewind($source_resource);

stream_filter_prepend($source_resource,'filtername',STREAM_FILTER_READ);

var_dump(stream_copy_to_stream($source_resource, fopen('php://memory', 'wb')));

Expected result:
----------------
bool(false)

Actual result:
--------------
int(0)