[php-src] Issue #20893: Assertion failure in check_node_running_in_fiber with generator in destructor

Issue: https://github.com/php/php-src/issues/20893
Author: vi3tL0u1s

### Description

The following code:

```php
<?php
class a {
    static $b;
    static $max = 2.;
    function __destruct() {
        if (self::$max-- < 0) return;
        self::$b = $this;
        static $gen = (function() {
            $from = (function () {
                x:$n[] = new a;
                yield;        
            })();
            try { yield from $from; } finally {}
        })();
        $fiber = new Fiber(function () use ($gen) {
            $gen->current();
            $gen->next();
        });
        $fiber->start();
    }
}
new a;
```

```
php: /path/to/php-src/Zend/zend_generators.c:217: check_node_running_in_fiber: Assertion `generator->execute_data' failed.
Aborted
```

## Commit

`c518a6ba8bf7a3eb6551424c7ca90dfa06b01b15`

## Configurations

```
./configure --enable-debug --enable-address-sanitizer --disable-shared --with-pic --enable-mbstring --with-zlib
```

### PHP Version

```plain
PHP 8.6.0-dev (cli) (built: Jan  9 2026 14:43:36) (NTS DEBUG)
Copyright (c) The PHP Group
Zend Engine v4.6.0-dev, Copyright (c) Zend Technologies
    with Zend OPcache v8.6.0-dev, Copyright (c), by Zend Technologies
```

### Operating System

Ubuntu 22.04