Merged pull request https://github.com/scylladb/scylla/pull/5980 by Piotr Jastrzębski, based on https://github.com/scylladb/scylla/pull/5976 by Juliusz Stasiewicz: "If base mutation has at least one row tombstone, its preimage log entry displays all the base columns." Fixes #5709 Tests: unit(dev)