[Dynamo] Preserve source_fn in node.meta (#92399)
Sample value from the test case `test_export_with_stack_trace`
node.target | node.meta["source_fn"]
-- | --
aten.randn.default | <built-in method randn of type object at 0x7f8683263108>
aten.t.default | < built-in function linear >
aten.mm.default | < built-in function linear >
aten.cos.default | <built-in method cos of type object at 0x7f8683263108>
aten.relu.default | relu
aten.add.Tensor | < built-in function add >
Pull Request resolved: https://github.com/pytorch/pytorch/pull/92399
Approved by: https://github.com/jerryzh168, https://github.com/yanboliang
