Fix aten.copy device mismatch bug in FakeTensor (#102664)
Fixes `pytest ./generated/test_yizhou_wang_RODNet.py -k test_000` failure in https://github.com/pytorch/pytorch/issues/92670.
FakeTensor would raise an error upon trying to run `aten.copy` with inputs with different devices, although this is allowed behavior.
Also fix `aten.slice_scatter`, since it also takes args with different devices.
Pull Request resolved: https://github.com/pytorch/pytorch/pull/102664
Approved by: https://github.com/yanboliang
