[PATCH 3/3] linux: Revert the use of sched_getaffinity on get_nproc (BZ #28310)

[Florian Weimer]

* Adhemerval Zanella:

> +  /* The /proc/stat format is more uniform, use it by default.  */

This comment seems outdated.  Rest looks okay (but I didn't run the full
test suite).

Thanks,
Florian