Remove conda env activation when tuning gpu (#1646)
Summary:
Test workflow: https://github.com/pytorch/benchmark/actions/runs/4966690518
Pull Request resolved: https://github.com/pytorch/benchmark/pull/1646
Reviewed By: janeyx99
Differential Revision: D45841929
Pulled By: xuzhao9
fbshipit-source-id: 0b380df17afafce1fb9350e9e509b9f516bfec21
