Context

The test-non-standard task family is shared by the encryption, load balancer, doctest, and PyOpenSSL suites, and the build variant decides which suite a task actually runs. Task names and tags do not identify the suite they run, which makes failures harder to attribute and keeps every suite from handling its own matrix.

PYTHON-6112 split the encryption runs by sync and async at the variant level. With per-suite task families, that mode belongs in the tasks themselves.

Definition of done

* Each suite has its own task family, and a task's name and tags identify the suite it runs.
* All of the encryption tests are grouped by distro and are split by sync/async.

* Load balancer tests are split by sync/async and run the full suite.
* The pinned PR build and the coverage tasks from PYTHON-6112 are kept.

Pitfalls

The suites currently share selection and setup paths; the refactor must not change what runs on PRs or break the suites' environment setup. The task matrix will grow for suites that reuse the encryption matrix today; keep that deliberate.