Description:
------------
It seems I've found a curious undocumented feature of the code execution "finally" after the shutdown_function.

Test script:
---------------
<?php
register_shutdown_function(function () {
    echo 'BYE BY SHUTDOWN', PHP_EOL;

    register_shutdown_function(function () {
        echo 'BYE BY LAST SHUTDOWN', PHP_EOL;
    });
});
function shutdown(): \Generator
{
    try {
        yield;
    } finally {
        echo 'PHP SUPER SHUTDOWN', PHP_EOL;
    }
}

$generator = shutdown();
$generator->rewind();

Expected result:
----------------
Code from finally executed never, since the generator is not iterated until the end, or "finally" code executed before shutdown_function.

php test.php 
BYE BY SHUTDOWN
BYE BY LAST SHUTDOWN

Actual result:
--------------
php test.php 
BYE BY SHUTDOWN
BYE BY LAST SHUTDOWN
PHP SUPER SHUTDOWN


Code from finally block executed after ALL shutdown_functions.