The Jenkins#unlabeledLoad LoadStatistics incorrectly counts labeled jobs from computeQueueLength().
Steps to reproduce:
- Create a job with a label 'foo'
- Run the job and ensure it is the only job in the queue
- Evaluating Jenkins.getInstance().unlabeledLoad.computeQueueLength() will return 1
This causes the Jenkins.unlabeledLoadProvisioner to provision slaves with null labels even though they will not be able to run the labeled jobs.