Deadlock in DB cleaner - build #18165918

https://gitlab.com/gitlab-org/gitlab-ee/builds/18165918

I've seen this a few times now, I'm not sure if it's EE-only or not. Sample backtrace:

  1) Discussion Comments Issue behaves like discussion comments clicking "Comment" will post a comment
     Failure/Error: DatabaseCleaner.clean

     ActiveRecord::StatementInvalid:
       PG::TRDeadlockDetected: ERROR:  deadlock detected
       DETAIL:  Process 119 waits for AccessExclusiveLock on relation 17244 of database 16384; blocked by process 93.
       Process 93 waits for AccessShareLock on relation 16567 of database 16384; blocked by process 119.
       HINT:  See server log for query details.
       : TRUNCATE TABLE "public"."abuse_reports", "public"."appearances", "public"."application_settings", "public"."approvals", "public"."approvers", "public"."audit_events", "public"."award_emoji", "public"."broadcast_messages", "public"."chat_names", "public"."ci_runner_projects", "public"."ci_runners", "public"."ci_triggers", "public"."ci_pipeline_schedules", "public"."ci_builds", "public"."identities", "public"."index_statuses", "public"."keys", "public"."issue_metrics", "public"."deployments", "public"."emails", "public"."environments", "public"."deploy_keys_projects", "public"."events", "public"."feature_gates", "public"."features", "public"."forked_project_links", "public"."geo_nodes", "public"."historical_data", "public"."issue_links", "public"."label_links", "public"."ldap_group_links", "public"."lfs_objects", "public"."lfs_objects_projects", "public"."lists", "public"."members", "public"."merge_request_diffs", "public"."milestones", "public"."merge_requests_closing_issues", "public"."notification_settings", "public"."notes", "public"."oauth_access_tokens", "public"."oauth_applications", "public"."personal_access_tokens", "public"."pages_domains", "public"."path_locks", "public"."project_features", "public"."project_group_links", "public"."project_import_data", "public"."project_mirror_data", "public"."project_statistics", "public"."push_rules", "public"."redirect_routes", "public"."releases", "public"."protected_tags", "public"."protected_branches", "public"."routes", "public"."sent_notifications", "public"."services", "public"."snippets", "public"."spam_logs", "public"."trending_projects", "public"."taggings", "public"."tags", "public"."todos", "public"."timelogs", "public"."uploads", "public"."user_agent_details", "public"."users_star_projects", "public"."approver_groups", "public"."namespace_statistics", "public"."ci_pipelines", "public"."ci_variables", "public"."chat_teams", "public"."issue_assignees", "public"."container_repositories", "public"."label_priorities", "public"."geo_event_log", "public"."oauth_access_grants", "public"."merge_request_metrics", "public"."geo_repository_updated_events", "public"."ci_sources_pipelines", "public"."ci_trigger_requests", "public"."boards", "public"."oauth_openid_requests", "public"."users", "public"."namespaces", "public"."projects", "public"."project_authorizations", "public"."labels", "public"."web_hooks", "public"."protected_branch_merge_access_levels", "public"."protected_branch_push_access_levels", "public"."merge_requests", "public"."remote_mirrors", "public"."protected_tag_create_access_levels", "public"."issues", "public"."subscriptions", "public"."system_note_metadata", "public"."u2f_registrations", "public"."web_hook_logs" RESTART IDENTITY CASCADE;
     Shared Example Group: "discussion comments" called from ./spec/features/discussion_comments/issue_spec.rb:15
     # ./spec/support/db_cleaner.rb:29:in `block (2 levels) in <top (required)>'
     # ./spec/spec_helper.rb:84:in `block (2 levels) in <top (required)>'
     # ------------------
     # --- Caused by: ---
     # PG::TRDeadlockDetected:
     #   ERROR:  deadlock detected
     #   DETAIL:  Process 119 waits for AccessExclusiveLock on relation 17244 of database 16384; blocked by process 93.
     #   Process 93 waits for AccessShareLock on relation 16567 of database 16384; blocked by process 119.
     #   HINT:  See server log for query details.
     #   ./spec/support/db_cleaner.rb:29:in `block (2 levels) in <top (required)>'