make tests for empty inputs check zero parameter grads

[ngimel]

Make batch norm with empty inputs return zero parameter gradients. Now batch norm, group norm and convolutions now return zero grads for parameters, so make tests check that. Fixes some bullet points in #12013 (interpolate is not fixed by this PR, is being fixed in other PRs)

[kostmo]

💊 CircleCI build failures summary and remediations

As of commit bec1e35:

None of the build failures appear to be your fault.

• 2/2 broken upstream at merge base 821b6aa since Jan 30

  Please rebase on the viable/strict branch (expand for instructions)

  If your commit is newer than viable/strict, you can try basing on an older, stable commit:

  git fetch origin viable/strict
  git rebase --onto viable/strict $(git merge-base origin/master HEAD)
  

  If your commit is older than viable/strict:

  git fetch origin viable/strict
  git rebase viable/strict
  

  Check out the recency history of this "viable master" tracking branch.

Detailed failure analysis

One may explore the probable reasons each build failed interactively on the Dr. CI website.

🚧 2 upstream failures recognized by patterns:

These builds matched patterns, but were probably caused by upstream breakages:

• pytorch_linux_backward_compatibility_check_test from Jan 29
• pytorch_linux_xenial_py2_7_9_test from Jan 30 until Jan 30

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This comment has been revised 5 times.

[albanD]

I think you're missing the test for batchnorm no?
Otherwise looks good.

[ngimel]

I think you're missing the test for batchnorm no?

Tests for batch norm were already present, they just did not check parameter gradients.

[albanD]

Right I was confused because you add a test for convtranspose :)

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[facebook-github-bot]

@ngimel merged this pull request in 29fabb1.