cleanup and improve software updater tests

[choksi81]

The software updater tests need to be cleaned up, made easier to run, and made possible to automate (at least some of them should be possible to automate on some OSs).

It needs to be clearer when there is an error, as they currently will say success when only parts of the test were successful even though other parts failed, e.g. #531. At a minimum, if it is too difficult to state success with absolute certainty, the output of the tests should make clear that apparent success does not mean actual success and provide, in the output, the information the human running the tests needs in order to determine whether the test was truly successful.

[choksi81]

Author: jsamuel
As they have gone this long without being cleaned up, it seems like it wouldn't be the end of the world to wait until the imminent rewrite of the updater, even if that is at least a few months out.

[choksi81]

Author: justinc
I think we should move these tests to utf. This port won't take long and I don't think we're running the tests much because we're using UTF primarily now.