safetensors.torch.save_model instead of save_file

[pauluskim]

What does this PR do?

RuntimeError: Some tensors share memory, this will lead to duplicate memory on disk and potential difference when loading them again:

By this instruction(https://huggingface.co/docs/safetensors/en/torch_shared_tensors), we should replace save_file with save_model.

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[LysandreJik]

cc @Narsil