Add attributes support for onnx cumsum op

[jinchen62]

No description provided.

[vivekkhandelwal1]

I'm still not very sure about the numerical correctness of this lowering.

[jinchen62]

@vivekkhandelwal1 Yeah you were right, there was mistake. I have made the changes. To explain what I'm doing, this is the example from https://onnx.ai/onnx/operators/onnx__CumSum.html#summary

input_x = [1, 2, 3]
axis=0
output = [1, 3, 6]
exclusive=1
output = [0, 1, 3]
exclusive=0
reverse=1
output = [6, 5, 3]
exclusive=1
reverse=1
output = [5, 3, 0]

For the exclusive case, basically it means it excludes the i-th element itself for the i-th position cumsum, so we just need to sub the original matrix from the cumsum result.

For the reverse case, we would just need to flip the matrix before and after the cumsum operation.

exclusive:
cumsum -> [1, 3, 6]
sub input -> [0, 1, 3]

reverse:
flip -> [3, 2, 1]
cumsum -> [3, 5, 6]
flip -> [6, 5, 3]

exclusive + reverse:
flip -> [3, 2, 1]
cumsum -> [3, 5, 6]
flip -> [6, 5, 3]
sub input -> [5, 3, 0]