Add optim nightly benchmarking workflow (#1521)
Summary:
Step 2 of https://github.com/pytorch/benchmark/pull/1520. This enables a nightly workflow for optim benchmarks that currently only PRINTS regressions + errors.
The next step is to work these into actual issues.
Pull Request resolved: https://github.com/pytorch/benchmark/pull/1521
Reviewed By: xuzhao9
Differential Revision: D44694155
Pulled By: janeyx99
fbshipit-source-id: 08bf57e71d41b441a26683c270bed9fc4fbacde2
