[GIT-PULLS] [php-src] PR #23251: PFA: Fix magic method resolution

Pull Request: https://github.com/php/php-src/pull/23251
Author: arnaud-lb

We conveniently use the function's scope for the scope of generated PFA closures as this allows const exprs referencing `self::` or `parent::` to behave normally:

However this affects method resolution for magic methods:

```
class C {
    private static function priv($a) {}
    public static function __call($name, $args) {}
}

// Sees only C::__call() 
$f = C::priv(?);

// Generates the following closure with scope=C: 

$f = function ($arguments0) {
    // Sees C::priv()
    static::priv($arguments0);
};

```

Fix by using the actual scope for PFAs of magic methods.

This should be enough as long as the generated closure doesn't inherit any `self::` or `parent::` expression from the magic method. Currently that's the case. If this changes we may have to rewrite these expressions, which I would like to avoid as this increases complexity and maintenance overhead.

The test `magic_scope.phpt` demonstrates the issue. `default_arg_scope.phpt` just checks relative-class resolution in default argument values.

Bug found by Ryan @ Calif.io