ns for fx: more meaningful error message when creating shadow model (#76468)
Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/76468
This makes the error message when copying an unsupported node more verbose.
This is useful to debug where specifically in a user model this is failing.
Test Plan:
1. hardcode this condition to hit
2. run NS tests
3. verify the exception now prints details about the offending node
Reviewed By: jerryzh168
Differential Revision: D35978652
Pulled By: vkuzo
fbshipit-source-id: 9cc93dfa46469bf6ef60aa38d4011041b6709df9
(cherry picked from commit c6e382c2a69aba6ba66740f238bc14446521a433)
