Matrix storage method in onnxruntiem c++ code

In the cpp/c interface in onnxruntime, the input matrix is ​​stored in row mode.

For example, 2*3 matrix, we use vector to represent, it has 6 elements, and the storage method is

* **｜＊* * (6-element plane storage), the vertical bar represents the line separator

First store the first line, then store the second line, and so on