[ONNX] Add constant fold for onnx::ReduceProd
One of the origins for `onnx::ReduceProd` is `aten::numel`.
Adding constant fold support for `onnx::ReduceProd` closes the gap
and enables symbolic shape inference for `aten::numel` nodes that
has static shape input.
One example is `torch.nn.EmbeddingBag` when input is 2d. An `Offset`
tensor will be created by `tensor.numel()`. This `Offset` can be
properly exported as constant now, if the input has static shape.
Pull Request resolved: https://github.com/pytorch/pytorch/pull/74082
Approved by: https://github.com/garymm
