standalone-shared/tests: modernize a bit

5 jobs for master in 0 seconds
Status Job ID Name Coverage
  External
passed ERP5.StandaloneDeploymentScriptTest-Debian.Stretch

00:25:16

passed SlapOS-Master.StandaloneDeploymentScriptTest-Debian.Buster

00:28:29

passed SlapOS-Master.StandaloneDeploymentScriptTest-Debian.Stretch

00:39:31

passed Wendelin.StandaloneDeploymentScriptTest-Debian.Buster

00:30:45

passed Wendelin.StandaloneDeploymentScriptTest-Debian.Stretch

00:36:27