[php-src] Issue #8183: New functions array_avg and array_median

Issue: https://github.com/php/php-src/issues/8183 Comment Author: niconoe- > Note that there is [PECL/stats](https://pecl.php.net/package/stats) which already may have such > functions. This is nice, I didn't know about PECL/stats! Unfortunately, this package looks like unmaintained but I understand the idea: if this does already exist elsewhere, there is no need to have it internally. However I'm feeling those addition to the PHP library is a good thing. I subscribed to the internals mailing list and I'll try to inform them and get some opinions, as sugested by @iluuu1994 . I understand the polarization as if internals would add every request, we'll probably have a functions with too much specific behaviors, but those functions are really technical. Implementation in userland is forcing people to build a specific wheel, but when such wheel is hyper-generic, it should be implemented in the language IMO.