[jit][oacr] Add some operators for Assistant NLU joint lite model (#40126)
Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/40126
These are needed for benchmarking / running our model, following Step 7 in the [Lite interpreter wiki](https://www.internalfb.com/intern/wiki/PyTorch/PyTorchDev/Mobile/Lite_Interpreter/#make-your-model-work-wit) and [this thread](https://www.internalfb.com/intern/qa/56293/atenemptymemory_format-missing-on-fb4a).
Test Plan: Sandcastle
Reviewed By: iseeyuan
Differential Revision: D22073611
fbshipit-source-id: daa46a39c386806be8d5d589740663e85451757e
