Add more tests for zero-sized bytes objects in `capi` tests

[sobolevn]

Bug report

Quoting @picnixz: #131343 (comment)

We could add more 0-size bytes tests in other functions as well I think. For instance PyBytes_FromObject(b'') is not tested.

PRs are welcome!

Linked PRs

• gh-131357: Add a set of asserts to test.test_capi.test_bytearray #131554
• [3.13] gh-131357: Add a set of asserts to test.test_capi.test_bytearray (GH-131554) #131601
• [3.12] gh-131357: Add a set of asserts to test.test_capi.test_bytearray (GH-131554) #131629
• gh-131357: Add tests for zero-sized bytes objects in test_bytes.py #134234
• [3.14] gh-131357: Add tests for zero-sized bytes objects in test_bytes.py (GH-134234) #134378
• [3.13] gh-131357: Add tests for zero-sized bytes objects in test_bytes.py (GH-134234) #134379
• gh-131357: Add some extra tests for empty bytes and bytearray #134458
• [3.14] gh-131357: Add some extra tests for empty bytes and bytearray (GH-134458) #134489
• [3.13] gh-131357: Add some extra tests for empty bytes and bytearray (GH-134458) #134490

[CHB-0r1s]

Can I work on this?

[sobolevn]

@CHB-0r1s sure, please go ahead! ❤