Directly calling __clone is allowed

Doing calls like $obj->__clone() is now allowed. This was the only magic method that had a compile-time check preventing some calls to it, which doesn't make sense. If we allow all other magic methods to be called, there's no reason to forbid this one.

Ref: https://wiki.php.net/rfc/abstract_syntax_tree#directly_calling_clone_is_allowed

Verified: https://3v4l.org/sqlsS

This is a bit hidden away in a RFC and not even mentioned in the changelogs in the manual, but it's a change in PHP behaviour and should not be that difficult to sniff out.