Correctly unpack tensor values (#11639)
Correctly unpack tensor values (#11639)

This change fixes two issues:

* protobuf 3.20 incompatibility
* Potential incorrect results on big-endian machines 

microsoft/onnxruntime,microsoft/onnxruntime,microsoft/onnxruntime,microsoft/onnxruntime,microsoft/onnxruntime,microsoft/onnxruntime,microsoft/onnxruntime,microsoft/onnxruntime,microsoft/onnxruntime,microsoft/onnxruntime,microsoft/onnxruntime,microsoft/onnxruntime