[nnc] Infer device type from nodes if inputs are all scalars (#59430)
Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/59430
With constant support added, we can now have fusion groups with only
scalar inputs. So, we need to get the device type from the nodes in the graph
rather than just the inputs.
ghstack-source-id: 130613871
Test Plan: new unit test; also see test_tracer test_trace_of_script
Reviewed By: navahgar
Differential Revision: D28891989
fbshipit-source-id: f9e824acbd4856216b85a135c8cb60a2eac3c628
