[php-src] Issue #8192: Cannot override DirectoryIterator::current() in 8.1

Issue: https://github.com/php/php-src/issues/8192 Author: zerocrates ### Description The following code: ```php <?php class OverrideValidDirectoryIterator extends DirectoryIterator { public function valid() { return null; } } class OverrideCurrentDirectoryIterator extends DirectoryIterator { public function current() { return null; } } ``` Resulted in this output: ``` Deprecated: Return type of OverrideValidDirectoryIterator::valid() should either be compatible with DirectoryIterator::valid(): bool, or the #[\ReturnTypeWillChange] attribute should be used to temporarily suppress the notice in /in/S7tkM on line 4 Fatal error: Declaration of OverrideCurrentDirectoryIterator::current() must be compatible with DirectoryIterator::current(): mixed in /in/S7tkM on line 10 ``` Obviously the first here is just a form of the documented 8.1 deprecation of overriding core classes without matching return typehints, but unlike for other methods on DirectoryIterator, overriding current() in this way is a fatal error and not an E_DEPRECATED, and the ReturnTypeWillChange attribute has no effect. ### PHP Version PHP 8.1.3 ### Operating System _No response_