BF16 requires special handling in this script
while it's a 2-bytes data, but view is 1-byte by default.
Switch to correct view before attempting byteswapping.
With this change correctly byteswapping models like
Meta-Llama-3-8B-Instruct-bf16-GGUF
should be possible.
* gguf-py: implement byteswapping for Q4_0
This is needed to byteswap Mistral model.
Also restore original shapes after byteswapping tensors.
It is not needed at the moment, but do it in case
they'd be used in future.
* Rework byteswapping code in gguf-py
Move out details from byteswapping tensor blocks code
Currently self.byte_order is never used.
Actually use it to byteswap read data to
allow reading big endian files on little endian systems
and vice versa.
Now it's possible to convert little-endian model
into a big-endian model and back
on a little-endian system.
