Remove a TODO for UpdateMergeRequestsWorker logging

We now have structured logging that tells us this information in a
better way.

app/workers/update_merge_requests_worker.rb

@@ -18,21 +18,7 @@ class UpdateMergeRequestsWorker # rubocop:disable Scalability/IdempotentWorker
     user = User.find_by(id: user_id)
     return unless user
 
-    # TODO: remove this benchmarking when we have rich logging
-    time = Benchmark.measure do
     MergeRequests::RefreshService.new(project, user).execute(oldrev, newrev, ref)
   end
-
-    args_log = [
-      "elapsed=#{time.real}",
-      "project_id=#{project_id}",
-      "user_id=#{user_id}",
-      "oldrev=#{oldrev}",
-      "newrev=#{newrev}",
-      "ref=#{ref}"
-    ].join(',')
-
-    Rails.logger.info("UpdateMergeRequestsWorker#perform #{args_log}") if time.real > LOG_TIME_THRESHOLD # rubocop:disable Gitlab/RailsLogger
-  end
   # rubocop: enable CodeReuse/ActiveRecord
 end

spec/workers/update_merge_requests_worker_spec.rb

@@ -26,17 +26,5 @@ describe UpdateMergeRequestsWorker do
 
       perform
     end
-
-    context 'when slow' do
-      before do
-        stub_const("UpdateMergeRequestsWorker::LOG_TIME_THRESHOLD", -1)
-      end
-
-      it 'logs debug info' do
-        expect(Rails.logger).to receive(:info).with(a_string_matching(/\AUpdateMergeRequestsWorker#perform.*project_id=#{project.id},user_id=#{user.id},oldrev=#{oldrev},newrev=#{newrev},ref=#{ref}/))
-
-        perform
-      end
-    end
   end
 end