Fixes squeezenet hierarchical batching. (#609)
Summary:
When doing hierarchical batching, the code should call the optimizer outside of the batch loop.
Pull Request resolved: https://github.com/pytorch/benchmark/pull/609
Reviewed By: dzhulgakov
Differential Revision: D32841042
Pulled By: xuzhao9
fbshipit-source-id: ad4f55476dc86face9219bf2bdb2ade11d17bbbe
