Relying on a real-time clock like lowres_clock can be flaky (in particular in debug mode). Use manual_clock instead to harden the test against timing issues. Fixes #20322 Signed-off-by: Benny Halevy <bhalevy@scylladb.com>
To allow support for manual_clock instead of seastar::sleep. Signed-off-by: Benny Halevy <bhalevy@scylladb.com>