Make SubprocessWorker surface errors in more cases (#608)
Summary:
Fixes https://github.com/pytorch/benchmark/issues/606
Pull Request resolved: https://github.com/pytorch/benchmark/pull/608
Reviewed By: erichan1
Differential Revision: D32885284
Pulled By: xuzhao9
fbshipit-source-id: 18353158d3096010fdad938afcfa76f33350ffaf
