Flaky master due to `No space left on device` errors

Job #293563012 failed for gitlab-ce@42b8e6838e8d63dcad7641a6164d178e9e09262a:

      # --- Caused by: ---
      # PG::DiskFull:
      #   ERROR:  could not extend file "base/16385/22830": No space left on device
      #   HINT:  Check free disk space.
      #   ./vendor/ruby/2.6.0/gems/activerecord-5.2.3/lib/active_record/connection_adapters/postgresql_adapter.rb:611:in `async_exec_params'

  13) API::Pipelines GET /projects/:id/pipelines/:pipeline_id behaves like pipelines visibility table visibility_level: :public, builds_access_level: :private, public_builds: true, is_admin: false, user_role: :developer, response_status: 200 
      Failure/Error: let(:user)        { create(:user) }

      ActiveRecord::StatementInvalid:
        PG::DiskFull: ERROR:  could not extend file "base/16385/22830": No space left on device
        HINT:  Check free disk space.
        : INSERT INTO "users" ("email", "encrypted_password", "created_at", "updated_at", "name", "projects_limit", "username", "state", "confirmed_at", "notification_email", "incoming_email_token", "admin", "external", "can_create_group", "can_create_team", "hide_no_ssh_key", "hide_no_password", "project_view", "notified_of_own_activity", "preferred_language", "theme_id") VALUES ('user876@example.org', '$2a$04$NQ2sFpCfczGy4wpQqeOmy./vXzbuwfq0TBAEvlkTv99C1zX1fqrvm', '2019-09-12 07:52:52.263907', '2019-09-12 07:52:52.263907', 'John Doe876', 42, 'user876', 'active', '2019-09-12 07:52:52.250429', 'user876@example.org', '7b8iu3icayrlm9wbqayuc0e6q', FALSE, FALSE, TRUE, FALSE, FALSE, FALSE, 2, FALSE, 'en', 1) RETURNING "id"
      Shared Example Group: "pipelines visibility table" called from ./spec/requests/api/pipelines_spec.rb:406
      # ./vendor/ruby/2.6.0/gems/activerecord-5.2.3/lib/active_record/connection_adapters/postgresql_adapter.rb:611:in `async_exec_params'
      # ./vendor/ruby/2.6.0/gems/activerecord-5.2.3/lib/active_record/connection_adapters/postgresql_adapter.rb:611:in `block (2 levels) in exec_no_cache'
      # ./vendor/ruby/2.6.0/gems/activesupport-5.2.3/lib/active_support/dependencies/interlock.rb:48:in `block in permit_concurrent_loads'
      # ./vendor/ruby/2.6.0/gems/activesupport-5.2.3/lib/active_support/concurrency/share_lock.rb:187:in `yield_shares'
      # ./vendor/ruby/2.6.0/gems/activesupport-5.2.3/lib/active_support/dependencies/interlock.rb:47:in `permit_concurrent_loads'
      # ./vendor/ruby/2.6.0/gems/activerecord-5.2.3/lib/active_record/connection_adapters/postgresql_adapter.rb:610:in `block in exec_no_cache'
      # ./vendor/ruby/2.6.0/gems/activerecord-5.2.3/lib/active_record/connection_adapters/abstract_adapter.rb:581:in `block (2 levels) in log'
      # /usr/local/lib/ruby/2.6.0/monitor.rb:230:in `mon_synchronize'
      # ./vendor/ruby/2.6.0/gems/activerecord-5.2.3/lib/active_record/connection_adapters/abstract_adapter.rb:580:in `block in log'
      # ./vendor/ruby/2.6.0/gems/activesupport-5.2.3/lib/active_support/notifications/instrumenter.rb:23:in `instrument'
      # ./vendor/ruby/2.6.0/gems/activerecord-5.2.3/lib/active_record/connection_adapters/abstract_adapter.rb:571:in `log'
      # ./vendor/ruby/2.6.0/gems/activerecord-5.2.3/lib/active_record/connection_adapters/postgresql_adapter.rb:609:in `exec_no_caRunning after script...