Adding Adapative Autorange to benchmark utils. (#44607)
Summary:
Fixes https://github.com/pytorch/pytorch/issues/44219
Rebasing https://github.com/pytorch/pytorch/pull/44288 and fixing the git history.
This allows users to bencmark code without having to specify how long to run the benchmark. It runs the benchmark until the variance (IQR / Median) is low enough that we can be confident in the measurement.
Pull Request resolved: https://github.com/pytorch/pytorch/pull/44607
Test Plan: There are unit tests, and we manually tested using Examples posted in git.
Reviewed By: robieta
Differential Revision: D23671208
Pulled By: bitfort
fbshipit-source-id: d63184290b88b26fb81c2452e1ae701c7d513d12
