ao migration: delete unused test class (#94420)
Summary:
This test case is dead code. A newer version of this code
exists in `test/quantization/ao_migration/test_quantization.py`. I
think this class must have been mistakenly left during a refactor.
Deleting it.
Test plan: CI
Pull Request resolved: https://github.com/pytorch/pytorch/pull/94420
Approved by: https://github.com/jerryzh168
