[TEST] Kill Runtime when running test script

[levincent06]

It's a problem when Runtime is running when we try to run tests, since the tests try to spawn an instance of Runtime. In the test script before running the actual tests, detect if Runtime is already active and stop it. Note that Runtime may already be running because of systemd, so a solution may be running sudo systemctl stop dev_handler and printing a warning message that the command was automatically executed.