[php-src] Issue #8270: SplFileObject method seek doesn't work as expected

Issue: https://github.com/php/php-src/issues/8270 Author: ASiRoS ### Description The following code: ```php <?php $splFileObject = new SplFileObject('any.csv'); $splFileObject->setFlags( SplFileObject::READ_CSV | SplFileObject::READ_AHEAD | SplFileObject::SKIP_EMPTY | SplFileObject::DROP_NEW_LINE ); $splFileObject->seek(0); $splFileObject->key(); // 0 Returns as expected $splFileObject->seek(1); $splFileObject->key(); // 1 Returns as expected $splFileObject->seek(2); $splFileObject->key(); // 1 But if we give anything more than 1, it will return 1 ``` Resulted in this output: ``` Seek doesn't get you to the expected line, but instead gets you to the second one (1). ``` But I expected this output instead: ``` Seek will move to the expected lines that exists. ``` seek works fine for PHP 7.4 and PHP 8.1, but results in this error for PHP 8.0 ### PHP Version PHP 8.0.16 ### Operating System Ubuntu 20.04