Fix inheritance in TestDataLoaderUtil (#85018)
TestDataLoaderUtils needs to run it's parent class's setUp method to actually disable flaky tests (see https://github.com/pytorch/pytorch/issues/70516#issuecomment-1247045072 for details)
Pull Request resolved: https://github.com/pytorch/pytorch/pull/85018
Approved by: https://github.com/clee2000, https://github.com/huydhn
