(PUP-1485) Don't use master when we want compilation to fail

Previously, this test assumed that outside of a `with_puppet_running_on`
block, the puppet master would not be running. This is true in the
FOSS test environment, but when we test against PE there is always a
master running. By using a name that is guaranteed to not be a puppet
server, we can ensure the agent is always incapable of getting a
catalog.