Improve the model-stableness workflow to dump stableness result in YAML (#1483)
Summary:
As titled.
CPU test: https://github.com/pytorch/benchmark/actions/runs/4411055601
GPU test: https://github.com/pytorch/benchmark/actions/runs/4416155469
Pull Request resolved: https://github.com/pytorch/benchmark/pull/1483
Reviewed By: weiwangmeta
Differential Revision: D44064597
Pulled By: xuzhao9
fbshipit-source-id: c1d95048d66abc4c7465d10fd2ca904b5f170240