New review comment by Chocimier on void-packages repository

https://github.com/void-linux/void-packages/pull/31811#discussion_r680208579

Comment:
> Maybe we don't need `disable_parallel_check` altogether?

Successful multicore compilation with tests broken when running in parallel will likely happen.

> `disable_parallel_build` also implies `disable_parallel_check`, which isn't obvious

Documenting that should be enough. You could also export additional XBPS_MAX_MAKEJOBS or so and read it for check if disable_parallel_build is on if you prefer, just make sure to export that in right places.