Currently server.sh defaults to executing the java process in the foreground, however we also provide the LAUNCH_ISPN_IN_BACKGROUND env variable which executes the Java process in the background and forwards any OS signals to it.

As OS signals are correctly forwarded to the background process by the server.sh script, we should only execute the server in this way. This removes the need for setting the LAUNCH_ISPN_IN_BACKGROUND in the image and tests, whilst removing one other knob from the configuration.