Fix stuck jobs tests

spec/workers/stuck_ci_jobs_worker_spec.rb

@@ -106,7 +106,7 @@ describe StuckCiJobsWorker do
     end
 
     it 'does drop job' do
-      expect_any_instance_of(Ci::Build).to receive(:drop)
+      expect_any_instance_of(Ci::Build).to receive(:drop).and_call_original
       worker.perform
     end
   end
@@ -117,7 +117,7 @@ describe StuckCiJobsWorker do
     let(:worker2) { described_class.new }
 
     it 'is guard by exclusive lease when executed concurrently' do
-      expect(worker).to receive(:drop).at_least(:once)
+      expect(worker).to receive(:drop).at_least(:once).and_call_original
       expect(worker2).not_to receive(:drop)
       worker.perform
       allow_any_instance_of(Gitlab::ExclusiveLease).to receive(:try_obtain).and_return(false)
@@ -125,8 +125,8 @@ describe StuckCiJobsWorker do
     end
 
     it 'can be executed in sequence' do
-      expect(worker).to receive(:drop).at_least(:once)
-      expect(worker2).to receive(:drop).at_least(:once)
+      expect(worker).to receive(:drop).at_least(:once).and_call_original
+      expect(worker2).to receive(:drop).at_least(:once).and_call_original
       worker.perform
       worker2.perform
     end