bpo-42213: Remove redundant cyclic GC hack in sqlite3 by erlend-aasland · Pull Request #26517 · python/cpython

The sqlite3 module now fully implements the GC protocol, so there's no
need for this workaround anymore.

• Add and use managed resource helper for connections using TESTFN
• Sort test imports
• Split open-tests into their own test case

https://bugs.python.org/issue42213

Automerge-Triggered-By: GH:vstinner