chiwwang

This looks ok for me. @haowhsu-quic @shewu-quic @chunit-quic @winskuo-quic , could you guys find a chance to give the script a try? I think this depends on Hutton's PRs. We...

> Yes, I think the most of PRs have been merged. Thanks for cclai's effort. But we also need the proper calibration for quantized llama. I think [this PR](https://github.com/pytorch/executorch/pull/4452) should...

> > @shewu-quic great job! does it support llama2 7b? > > Unfortunately, it does not support llama2 7b in this draft, but we are actively working on enabling llama2...

This PR is somehow based on https://github.com/pytorch/executorch/pull/4142 We will continue llama2-7b tasks by this PR.