FX: ensure node stack trace survives copying (#69368)
Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/69368
Before this PR, copying a node would lose the stack trace. This PR
ensures that the stack trace is preserved across copies.
This is useful because quantization passes would like to start
allowing the user to preserve stack traces, and we use the copy
behavior.
Test Plan:
```
python test/test_fx.py TestFX.test_stack_traces
```
Imported from OSS
Reviewed By: jamesr66a
Differential Revision: D32835248
fbshipit-source-id: 91610fd8d05f5683cfa5e11fb6f9f3feacb8e241
