rpc : proper handling of data pointers to CPU buffers (#21030)
The compute graph may contain tensors pointing to CPU buffers. In these
cases the buffer address is serialized as 0 and sent over the wire.
However, the data pointer is serialized as-is and this prevents proper
validation on the server side. This patches fixes this by serializing
the data pointer as 0 for non-RPC buffers and doing proper validation on
the server side.
closes: #21006