[dynamo] fix general attr on tensor for user-provided attributes (#94332)
**Problem**: For a tensor `x`, you can assign `x.my_attr = 3.14` and then later access it. Dynamo does not support this right now; it errors out with an AttributError (it was broken in #91840).
**Fix**: This fixes the problem by catching AttributeErrors in dynamo if we try to access an attr that does not exist on a standard torch.Tensor.
**Tests**: Added tests for accessing and setting attributes to make sure dynamo does not error out.
Pull Request resolved: https://github.com/pytorch/pytorch/pull/94332
Approved by: https://github.com/yanboliang
