[php-src] Issue #21059: SIGSEGV in OPCache Preloading when using Typed Class Constants with Closures

Issue: https://github.com/php/php-src/issues/21059
Author: MariusJam

### Description

Hello,

A Segmentation Fault occurs when an OPCache preloaded class contains a typed constant assigned to a Closure.

I have made a reproducer : https://github.com/MariusJam/opcache-crash-const-closure-reproducer

Please note that I am not familiar with C debugging. I relied on AI assistance to get and interpret the strace logs and create this minimal reproducer.




### PHP Version

```plain
PHP 8.5.2 (cli) (built: Jan 16 2026 23:16:53) (NTS)
Copyright (c) The PHP Group
Built by https://github.com/docker-library/php
Zend Engine v4.5.2, Copyright (c) Zend Technologies
    with Zend OPcache v8.5.2, Copyright (c), by Zend Technologies
```

### Operating System

Alpine or Debian (Docker)