[php-src] Issue #8308: The return value of mb_list_encodings() doesn't contain 'SJIS-win'

Issue: https://github.com/php/php-src/issues/8308 Author: sji-il ### Description The following code: ```php <?php var_dump(mb_list_encodings()); ``` https://3v4l.org/GH0Gj Resulted in this output: - contains 'SJIS-win' But I expected this output instead: - contains 'CP932' and 'SJIS', but no 'SJIS-win' [As of PHP 8.1](https://github.com/php/php-src/commit/e2459857afdf70ed4bc23bc7f614e9f383eb3072), SJIS-win is an alias of CP932, thus the return value of [mb_list_encodings()](https://www.php.net/manual/en/function.mb-list-encodings.php) never contains 'SJIS-win'. This breaks BC. Some libraries have functions which receive one or more encoding names as arguments, and they often validate the input by the return value of mb_list_encodings(). This should be reverted, or fixed, or at least documented as an incompatible change. ### PHP Version PHP 8.1.0 ### Operating System _No response_