[php-src] Issue #12967: `set_error_handler` should be able to handle fatal error once

Issue: https://github.com/php/php-src/issues/12967 Author: mvorisek ### Description Currently, fatal error can be handled, but it is not possible to do so using handler set by set_error_handler. An example is here: https://github.com/phpstan/phpstan-src/blob/1.10.50/src/Command/CommandHelper.php#L137-L154 This is a feature request to allow error handler to handle fatal error when php enters into shutdown before the 1st shutdown handler is executed.