Reduce needless copying when returning lists of tensors in the JIT interpreter. (#21690)
Summary:
This fixes the JIT performance gap reported in https://twitter.com/VahidK/status/1138677898439561216
Pull Request resolved: https://github.com/pytorch/pytorch/pull/21690
Differential Revision: D15783709
fbshipit-source-id: 23bb4acda6b60c27e95667e1d53c7d261a87167d
