Fixed num_channels!=3 normalization training (#20630)
* Fixed num_channels!=3 normalization training
* empty commit to trigger CI
* Empty-Commit for CircleCI
* Empty-Commit
* Empty Commit try-3: https://discuss.circleci.com/t/github-code-checkout-suddenly-failing/31558
* Empty commit to trigger CI
Co-authored-by: Lay Jain <layjain@basil.csail.mit.edu>
Co-authored-by: ydshieh <ydshieh@users.noreply.github.com>
