Check PyTorch version

[yifuwang]

Stack from ghstack (oldest at bottom):

• -> #67
• #66

When the installed PyTorch version is not nightly:

• Issue an warning if torch.compile is requested.
• Raise an error if both tensor-parallel and torch.compile are requested (tensor-parallel + torch.compile doesn't work on 2.1.2+cu121 due to a bug in functional collective. See https://github.com/pytorch-labs/gpt-fast/issues/64)