[Test] Changed verification method to a check if all tensor shapes are set and the output of the new node has specific value

[Test] Test for shape inference creates now a mixed model and performs shape inference. Afterwards it is executed to check if it still works

[Execution/Test] Added shape inference for custom nodes and fixed some pre-commit errors in the test files

[Test] Added first draft of shape inference test and onnx model in data path with one custom and one standard node