Since PHP 8.1, calling the `Reflection*::setAccessible()` methods is no longer necessary as reflected properties/methods/etc will always be accessible.
However, the method calls are still needed for PHP < 8.1.
As of PHP 8.5, calling the `Reflection*::setAccessible()` methods is now formally deprecated and will yield a deprecation notice, which will fail test runs.
As of PHP 9.0, the `setAccessible()` method(s) will be removed.
With the latter in mind, this commit prevents the deprecation notice by making the calls to `setAccessible()` conditional.
Silencing the deprecation would mean, this would need to be "fixed" again come PHP 9.0, while the current solution should be stable, including for PHP 9.0.
Ref: https://wiki.php.net/rfc/deprecations_php_8_5#extreflection_deprecations
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