Finalize deletion of orphaned build rows
After #485607 (closed) is complete we must finalize the migration: https://docs.gitlab.com/ee/development/database/batched_background_migrations.html#finalize-a-batched-background-migration
After #485607 (closed) is complete we must finalize the migration: https://docs.gitlab.com/ee/development/database/batched_background_migrations.html#finalize-a-batched-background-migration