Add bisection interactive mode for debugging.

[xuzhao9]

In https://github.com/pytorch/benchmark/actions/runs/7745905863, the bisection returns empty result where it should find the root cause commit of hf_longformer bugfix.

1. Fix a bug where bisection returns empty result: the regression detector will change the commit metrics, so we need to pass in a copy of the commit digest.
2. Add an interactive mode for easier debugging.

Test Plan:

To use the interactive mode, run (pytorch repo sources are still needed):

python bisection.py --work-dir ~/work/bisection/test --torch-repos-path ~/tmp/torch_srcs --config ~/work/bisection/test/regression-2024-02-01.yaml --torchbench-repo-path $PWD --output ~/work/bisection/test/output.json --interactive

Run the nightly bisection workflow on 2024-02-01:

https://github.com/pytorch/benchmark/actions/runs/7793771518

The workflow finds the right commit: #2151

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@xuzhao9 has imported this pull request. If you are a Meta employee, you can view this diff on Phabricator.

[aaronenyeshi]

This is a great addition!

[facebook-github-bot]

@xuzhao9 merged this pull request in ab07f16.