Use tools/print_test_stats.py in GHA (#57647)
Summary:
Judging from https://github.com/pytorch/pytorch/issues/57584, it seems like the test-reports artifact was originally intended to be downloaded to `$PWD/test-reports` instead of just directly into `$PWD`. To minimize confusion, this PR changes it to download into `test/test-reports`, which should match where the files came from in the `test` step anyway.
TODOs:
- [x] change the extract path for test-reports
- [x] install Python dependencies
- [x] call `tools/print_test_stats.py`
- [x] use deep clone to allow `git` commands
- [x] correctly set `CIRCLE_*` environment variables
- [x] set Scribe credentials
- [x] set AWS credentials
Pull Request resolved: https://github.com/pytorch/pytorch/pull/57647
Test Plan: CI.
Reviewed By: seemethere
Differential Revision: D28325833
Pulled By: samestep
fbshipit-source-id: cc322bad76747f59b764a1a0a863153bb26095e7
