Add data_consistency for BuildQueueWorker

Introduces data_consistency for the worker, under feature flag, disabled
by default.

app/workers/build_queue_worker.rb

@@ -10,6 +10,7 @@ class BuildQueueWorker # rubocop:disable Scalability/IdempotentWorker
   feature_category :continuous_integration
   urgency :high
   worker_resource_boundary :cpu
+  data_consistency :sticky, feature_flag: :load_balancing_for_build_queue_worker
 
   # rubocop: disable CodeReuse/ActiveRecord
   def perform(build_id)

config/feature_flags/development/load_balancing_for_build_queue_worker.yml

+---
+name: load_balancing_for_build_queue_worker
+introduced_by_url: https://gitlab.com/gitlab-org/gitlab/-/merge_requests/63212
+rollout_issue_url: https://gitlab.com/gitlab-org/gitlab/-/issues/332586
+milestone: '14.0'
+type: development
+group: group::memory
+default_enabled: false

spec/workers/build_queue_worker_spec.rb

+# frozen_string_literal: true
+
+require 'spec_helper'
+
+RSpec.describe BuildQueueWorker do
+  describe '#perform' do
+    context 'when build exists' do
+      let!(:build) { create(:ci_build) }
+
+      it 'ticks runner queue value' do
+        expect_next_instance_of(Ci::UpdateBuildQueueService) do |instance|
+          expect(instance).to receive(:tick).with(build)
+        end
+
+        described_class.new.perform(build.id)
+      end
+    end
+
+    context 'when build does not exist' do
+      it 'does not raise exception' do
+        expect { described_class.new.perform(123) }
+          .not_to raise_error
+      end
+    end
+  end
+
+  it_behaves_like 'worker with data consistency',
+                  described_class,
+                  feature_flag: :load_balancing_for_build_queue_worker,
+                  data_consistency: :sticky
+end