[php-src] Issue #20615: Assertion failure in check_node_running_in_fiber() when resuming a generator inside a Fiber destructor

Issue: https://github.com/php/php-src/issues/20615
Author: vi3tL0u1s

### Description

The following code:

```php
<?php
class a {
    static $b;
    static $max = 5.;
    function __destruct() {
        $a  = new a;
        static $gen = (function() {
            $from = (function () {
                $a = new a;
                yield;
            })();
            try {
                yield from $from;
            } finally {
            }
        })();
        $fiber = new Fiber(function () use ($gen, &$fiber) {
            $gen->next();
        });
        $fiber->start();
    }
}
new a;
```

Resulted in this output:
```
php: /path/to/php-src/Zend/zend_generators.c:217: _Bool check_node_running_in_fiber(zend_generator *): Assertion `generator->execute_data' failed.
Aborted
```

Commit:
```
56795d2810e
```

Build configuration:
```
CC="clang" CXX="clang++" CFLAGS="-fsanitize=address -g -O0" CXXFLAGS="-fsanitize=address -g -O0" LDFLAGS="-fsanitize=address" ./buildconf --force && ./configure --enable-debug --enable-address-sanitizer --disable-shared --with-pic --enable-mbstring --with-zlib
```


### PHP Version

```plain
PHP 8.6.0-dev (cli) (built: Nov 29 2025 14:32:34) (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