4-people-I-know assumes a sorting behaviour

[illicitonion]

Some of the tests, at least "Powernet email addresses", assume the answer is sorted.

We should probably either specify that this behaviour is expected, or use a comparison in the test which doesn't assert sorting.

While there are places where we want our trainees to notice an expected behaviour from how tests fail, and adapt to it, I feel like this isn't one of them - it's a very specific behaviour without much inherent justification in the problem, rather than a natural ambiguity in the problem which the tests could resolve.