[php-src] Issue #11902: Unclear "During class fetch: Uncaught" error

Issue: https://github.com/php/php-src/issues/11902 Author: PrinsFrank ### Description We have this error happen a couple times over the past few months, but it is unclear what the cause of it is: ``` Symfony\Component\ErrorHandler\Error\FatalError: During class fetch: Uncaught #0 /vendor/monolog/monolog/src/Monolog/Handler/AbstractProcessingHandler.php(24): null ``` Looking at the code, it is triggered in [zend_execute_API.c on line 1630](https://github.com/php/php-src/blob/efc73f24c30400f2c62420c19d0891bc4d891d90/Zend/zend_execute_API.c#L1630) Looking at the limited information and where the class is being called where the error consistently occurs, it looks like this class is autoloaded from code being registered in a shutdown handler, and it might be a process that is still running when the files for that autoload are already deleted. Can this be the cause? If so, is this a bug we should fix in the autoloader or is this a scenario that should never happen in PHP and that's why the message is unclear? ### PHP Version 8.1.21 ### Operating System Linux GKE 5.15.89