[compiler-rt] Relax pthread_getaffinity test to account for cgroups/docker

Fixes #58283

When running in a docker container you can have fewer cores assigned
to you than get_nrpoc would suggest.

Since the test just wants to know that interception worked, allow
any result > 0 and <= the global core count.

Reviewed By: MaskRay, vitalybuka

Differential Revision: https://reviews.llvm.org/D135677