Skip strategy=ddp_spawn, accelerator=cpu, python>=3.9 tests

[carmocca]

What does this PR do?

Fixes current master CI failures for:

• cpu (ubuntu-18.04, 3.9, oldest, stable)
• cpu (macOS-10.15, 3.9, oldest, stable)

Caused by pytorch/pytorch#49370

I don't think there's anything we can do here other than skipping the tests.

Does your PR introduce any breaking changes? If yes, please list them.

None

Before submitting

• Was this discussed/approved via a GitHub issue? (not for typos and docs)
• Did you read the contributor guideline, Pull Request section?
• Did you make sure your PR does only one thing, instead of bundling different changes together?
• [n/a] Did you make sure to update the documentation with your changes? (if necessary)
• [n/a] Did you write any new necessary tests? (not for typos and docs)
• Did you verify new and existing tests pass locally with your changes?
• Did you list all the breaking changes introduced by this pull request?
• [n/a] Did you update the CHANGELOG? (not for typos, docs, test updates, or internal minor changes/refactorings)

PR review

• Is this pull request ready for review? (if not, please submit in draft mode)
• Check that all items from Before submitting are resolved
• Make sure the title is self-explanatory and the description concisely explains the PR
• Add labels and milestones (and optionally projects) to the PR so it can be classified

cc @tchaton

[github-actions]

Build Error! No Linked Issue found. Please link an issue or mention it in the body using #<issue_id>