Tests test_total_space_limit_of_commitlog_with_large_limit and
test_total_space_limit_of_commitlog_with_medium_limit use too much
disk space and have too big execution time. Keep them in
scylla-dtest for now.
As a part of the porting process, remove unused imports and
markers, remove non-next_gating tests and tests marked with
`skip`, 'skip_if', and `xfail` markers.
test.py uses `commitlog` directory instead of dtest's
`commitlogs`.
Remove test_stop_failure_policy test because the way how it
provoke commitlog failure (change file permission) doesn't
work on CI.
Enable the test in suite.yaml (run in dev mode only)
