text: Title: Messages logged by `start_test` and `end_test` listener methods are ignored
  Body: If `start_test` or `end_test` listener method logs something using `robot.api.logger`, the messages don't end up to output.xml and log.html. Although they go to the syslog, the syslog isn't enabled by default and thus they are in practice ignored.
  
  I think this was a technical limitation earlier when tests could only contain keywords. Nowadays they have a generic `body` that can contain keywords, control structures and also messages. We just explicitly forward messages logged before any keyword or control structure has started to syslog.
  
  I'm not sure should this issue be considered a bug or an enhancement, but decided to go with the former. Either way, this is easy to fix.