Use GH cache for sccache on GH mac runners (#96142)
sccache added GH cache as a storage option, so try to use it for the GH provided mac runners.
My experiments with this are varied. I tried a couple of different releases and the first run with a cold cache took 1hr (v0.3.3), 1hr (v0.4.0 pre7), 2hr (v0.3.3).
Afterwards it usually takes 30 minutes but sometimes longer, but no longer than 1hr.
I am using v0.4.0 pre7 because they reduced the amount of configuration/env vars you need to set and the GH cache keys get managed by sccache.
Pull Request resolved: https://github.com/pytorch/pytorch/pull/96142
Approved by: https://github.com/huydhn, https://github.com/malfet
