Implement converter for `torch.ops.aten.bmm.default`

[gs-olive]

Schema: https://github.com/pytorch/pytorch/blob/bdecdfd202df3fa25fd9998070fd19fee4b14971/aten/src/ATen/native/native_functions.yaml#L1286-L1294

Docs:
https://pytorch.org/docs/stable/generated/torch.bmm.html

[bowang007]

closing per #2248