GitLab

* add USE_TORCH_XLA env

* rename torch_tpu to torch_xla

* better is_torch_xla_available; fix some fsdp and performance issues

* fix format

* fix bug when pjrt_device is cpu

* fix bug

* fix the deprecation handling

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Co-authored-by: anw90 <ang868@gmail.com>
Co-authored-by: wangang.wa <wangang.wa@alibaba-inc.com>