[php-src] Issue #8739: String corruption on deployments with php-fpm 8.1.6

Issue: https://github.com/php/php-src/issues/8739 Author: nono-gdv ### Description Hello, We experience seemingly random in-memory corruption of code when deploying new versions of our PHP app on php-fpm 8.1.6 on Linux. Here is a sample error message: ``` include(/space/www/api2019/data/releases/20220607140425/vendor/la�R�F): Failed to open stream: No such file or directory ``` This example happens in [the class loader from composer](https://github.com/composer/composer/blob/main/src/Composer/Autoload/ClassLoader.php). The beginning of the file name is correct, the end is obviously not. Another example (another release on another server): ``` Call to undefined function Symfony\Component\HttpFoundation\implode() ``` This bug is not easily reproducible, it happens in random-looking places in the code, sometimes but not always, on some servers but not others (we have 10 app servers, the bug appears on one server at a time, very rarely two, not on every release but more than half of them). When it happens, it looks like there is only one corrupted chunk of data; depending on the affected data, it may only cause a few real errors or basically prevent the code from working on the server at all. It generates errors for a few minutes. Restarting the fpm daemon fixes it; reloading it or running opcache_reset() does not. We will try to reproduce it on a staging server; at the moment I can only say it appears under load and not under light testing. It may or may not be related to #8731 (same app, same servers, seemingly fixed by downgrading to 8.0.19). I know this report is not really helpful, but I'm at a loss how to make it more useful. Downgrading to PHP 8.0.19 seems to fix the issue. ### PHP Version PHP 8.1.6 (cli) (built: May 17 2022 16:49:19) (NTS) ### Operating System Debian 10