torchvision: Allow torchvision-tests output

[mgorny]

Checklist:

• I want to mark a package as broken (or not broken):

  • Added a description of the problem with the package in the PR description.
  • Pinged the team for the package for their input.

• I want to archive a feedstock:

  • Pinged the team for that feedstock for their input.
  • Make sure you have opened an issue on the feedstock explaining why it was archived.
  • Linked that issue in this PR description.
  • Added links to any other relevant issues/PRs in the PR description.

• I want to request (or revoke) access to an opt-in CI resource:

  • Pinged the relevant feedstock team(s)
  • Added a small description explaining why access is needed

• I want to copy an artifact following CFEP-3:

  • Pinged the relevant feedstock team(s)
  • Added a reference to the original PR
  • Posted a link to the conda artifacts
  • Posted a link to the build logs

• I want to add a package output to a feedstock:

  • Pinged the relevant feedstock team(s)
  • Added a small description of why the output is being added.

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As discussed in conda-forge/torchvision-feedstock#107.