Test fixes (#106586)
Fix for https://github.com/pytorch/pytorch/issues/106548 and https://github.com/pytorch/pytorch/issues/106299.
The fallback was not actually testing fallback anymore now that we have a fake tensor rule for conv. Memory format fallback testing is also now exercised in test_ops.py `TestFakeTensor`.
Gc collect fixes the list_clearing test. I suspect their was a refcycle introduced which is making it flakey.
Pull Request resolved: https://github.com/pytorch/pytorch/pull/106586
Approved by: https://github.com/wconstab
