The primary goal of this test is to reproduce scylladb/scylladb#26040
so the fix (278019c328) can be backported
to older branches.
Scenario: connect via CQL as an anonymous user and verify that the
`sl:default` scheduling group is used. Before the fix for #26040
`main` scheduling group was incorrectly used instead of `sl:default`.
Control connections may legitimately use `sl:driver`, so the test
accepts those occurrences while still asserting that regular anonymous
queries use `sl:default`.
This adds explicit coverage on master. After scylladb#24411 was
implemented, some other tests started to fail when scylladb#26040
was unfixed. However, none of the tests asserted this exact behavior.
Refs: scylladb/scylladb#26040
Refs: scylladb/scylladb#26581Closesscylladb/scylladb#26589
(cherry picked from commit 8642629e8e)