pytorch

7aca9afd - [pytorch] remove boilerplate setQEngine() from PyTorch mobile predictors (#34556)

[pytorch] remove boilerplate setQEngine() from PyTorch mobile predictors (#34556) Summary: Pull Request resolved: https://github.com/pytorch/pytorch/pull/34556 According to https://github.com/pytorch/pytorch/pull/34012#discussion_r388581548, this `at::globalContext().setQEngine(at::QEngine::QNNPACK);` call isn't really necessary for mobile. In Context.cpp it selects the last available QEngine if the engine isn't set explicitly. For OSS mobile prebuild it should only include QNNPACK engine so the default behavior should already be desired behavior. It makes difference only when USE_FBGEMM is set - but it should be off for both OSS mobile build and internal mobile build. Test Plan: Imported from OSS Differential Revision: D20374522 Pulled By: ljk53 fbshipit-source-id: d4e437a03c6d4f939edccb5c84f02609633a0698