As per Jetty Issue#4492 which was created to report the failure to process requests we have been told that our code is wrong.
We need to
- see if we can remove the custom thread pools from `jenkins-test-harness` (it only is used to set the name of the Thread) ✔
- make sure other uses of Jetty in Jenkins are safe
- winstone ✔
- maven-hpi-plugin (run mojoe etc) ✔