gh-94808: Add coverage for bytesarray_setitem

[mdboom]

When both are provided, tp_ass_subscript takes precedence over tp_ass_item. Since bytesarray provides both, the existing test_setitem tests for bytesarray were not testing bytesarray_setitem, but bytesarray_ass_subscript. This is mostly fine, since Python code has to jump through some hoops to even call it, but a third-party library using PySequence_SetItem could potentially run into this uncovered case.

• Issue: Metabug: Improving C-level coverage #94808

[JelleZijlstra]

Looks good. Any reason you didn't mark this for backporting to 3.10?

[mdboom]

Looks good. Any reason you didn't mark this for backporting to 3.10?

No real reason not to -- for all these other coverage improvements linked to #94808, we've just been backporting to 3.11.

[miss-islington]

Thanks @mdboom for the PR, and @JelleZijlstra for merging it 🌮🎉.. I'm working now to backport this PR to: 3.10, 3.11.
🐍🍒⛏🤖

[miss-islington]

Sorry, @mdboom and @JelleZijlstra, I could not cleanly backport this to 3.11 due to a conflict.
Please backport using cherry_picker on command line.
cherry_picker dfcdee4a18ece6f7c4fe1aa5830ee861f8b15b24 3.11

[miss-islington]

Sorry @mdboom and @JelleZijlstra, I had trouble checking out the 3.10 backport branch.
Please backport using cherry_picker on command line.
cherry_picker dfcdee4a18ece6f7c4fe1aa5830ee861f8b15b24 3.10

[JelleZijlstra]

Thanks! I think it's good to backport new tests to the bugfix branches so we can be more confident in any future bugfixes. But testing on 3.11 is definitely more important.

Would you mind doing the manual backports? Feel free to skip 3.10 if you don't think it's worth it.