Use the same python version in MacOS workflows and add more debug messages (#98902)
After https://github.com/fairinternal/pytorch-gha-infra/pull/139 (https://github.com/fairinternal/pytorch-gha-infra/actions/runs/4683157903/jobs/8297905750), the flaky issue on MacOS points to sccache setup. There are several issues there:
* sccache is downloaded to `/usr/local/bin/sccache`. Surprisingly, the build script doesn't find it in some cases (probably the new runners), for example https://github.com/pytorch/pytorch/actions/runs/4681216666/jobs/8293519052 has `which sccache` returns nothing despite that the binary is there. In such case, `/usr/local/bin` is not in GitHub path.
* Once sccache is used. We need to use the correct sccache binary arch. Using sccache for x86-64 on M1 would end up with a x86-64 torch binary, i.e. https://hud.pytorch.org/pytorch/pytorch/commit/01e011b07c9ad2447f3061e33ec757f0c23cec6f
* We don't need to set the AWS secret key on MacOS runner anymore. The AWS M1 runner has access to S3 cache via its IAM profile while GitHub x86-64 runner uses GitHub cache https://github.com/pytorch/pytorch/pull/96142
Other minor changes:
* The same python version is used in both MacOS build and test jobs. This is set by the workflow via `python-version` parameter
* Add some debug information about the python version is used to run the test
Pull Request resolved: https://github.com/pytorch/pytorch/pull/98902
Approved by: https://github.com/seemethere, https://github.com/malfet
