[ONNX] Fix circular padding to support dynamic axes (#95647)
This commit fixes a bug where the ONNX exporter for circular padding queried the input tensor shape in order to get the correct 'end' index for a slice node. This doesn't work when the axis in question is has dynamic size. The commit fixes this by setting the 'end' index to INT_MAX, which is the recommended way of slicing to the end of a dimension with unknown size per ONNX spec.
See https://onnx.ai/onnx/operators/onnx__Slice.html
Also adds a regression test.
Pull Request resolved: https://github.com/pytorch/pytorch/pull/95647
Approved by: https://github.com/BowenBao
