[ONNX] Add Support on 0d tensor Broadcast (#87211)
I am not sure if this will break things ...
Although 0d tensor is an undefined behavior in ONNX spec, I did some experiments and found that ONNX shape inference actually provides 0d as inference from 0d and 1d Op calculations, and the bug happened in Broadcast function. But still, if this breaks things really bad, I think we can put 0d tensor handling on hold, as it's not very common usage on models?
Pull Request resolved: https://github.com/pytorch/pytorch/pull/87211
Approved by: https://github.com/jcwchen, https://github.com/BowenBao
