torch.split() replace slicing on out-of-place inference

[glenn-jocher]

Simplified export, similar profiling on PyTorch inference.

🛠️ PR Summary

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🌟 Summary

Improved tensor operations in YOLOv5 model code.

📊 Key Changes

• Replaced a set of tensor operations with a more concise and readable split operation (y.split method).
• The bounding box predictions (xy and wh) and confidence score calculations are now more clearly separated by using the split operation.
• The updated code now concatenates the separated tensors back together after processing.

🎯 Purpose & Impact

• The purpose is to enhance code readability and potentially efficiency by using the more modern tensor operations.
• This change could make future maintenance and updates more straightforward, reducing the likelihood of bugs.
• Users can expect the revised code to have similar performance with improved clarity, which might facilitate customization and further development.