Revert "Use cpuinfo to determine c10::ThreadPool thread number (#107010)"
This reverts commit ad0476540dcaf07aa6e3639f6c60ee820d5f3f99.
Reverted https://github.com/pytorch/pytorch/pull/107010 on behalf of https://github.com/izaitsevfb due to Breaks internal meta builds ([comment](https://github.com/pytorch/pytorch/pull/107010#issuecomment-1679866821))
