[FIX][ONNX][RELAX] Add support for dynamic ShapeExpr in Slice, Squeeze and Flatten

[PatrikPerssonInceptron]

Squeeze

I added a tuple wrapping around axis when sending it to _np.squeeze since it does not support list objects. I added an additional check to see if the data is a ShapeExpr. If this is the case I perform the inverse of the operations done in the Unsqueeze operation.

Slice

I fixed a bug where the dimensions were assumed to be of IntImm data type by adding an additional check to handle the constant and dynamic case separately.

Flatten

I fixed a bug where the dimensions were assumed to be of IntImm data type by adding an additional check to handle the constant and dynamic case separately.

Split

I replaced asnumpy with numpy since asnumpy is deprecated. I added a call to .item() to convert from numpy data types to python primitives.

Regression Tests

I extracted generate_random_value function from generate_random_inputs. I added isinstance(tvm_out, (int, float, bool)) in check_correctness since the VM can return python primitive types

Squeeze

I added a test case for squeeze with constant input since it was missing I added a test case for squeeze with dynamic input shape I added a test case for squeeze with dynamic shape expression

Slice

I added a test case for slice with dynamic shape expression

Split

I fixed a bug in test_split which caused the constant split case never to occur

[tqchen]

cc @Hzfengsy can you help to take a look

[Hzfengsy]

Thanks for the contribution, please add a regression test :)

[PatrikPerssonInceptron]

My pleasure, where exactly in the code should I add the regression tests? :)

[Hzfengsy]

tests/python/relax/test_frontend_onnx.py would be great:)

[Hzfengsy]

LGTM. Thanks for the contribution!!!

[PatrikPerssonInceptron]

Happy to help!