Add `sched_setaffinity` check from libgomp to `valgrind.sup` (#37532)
Summary:
- It's valid to call `sched_setaffinity` with nullptr
- The call is coming from libomp which should be valgrind safe
Pull Request resolved: https://github.com/pytorch/pytorch/pull/37532
Test Plan: CI
Differential Revision: D21311252
Pulled By: malfet
fbshipit-source-id: a325f97741b997738c35759d02fcc34c1cb44d95
