Add ability to add up before() runtime with it() runtime

[Almad]

--slow is highlighting only long running tests, measuring only time it() took to execute.

This leads to missed slow tests if slow part is hidden in test preparation (in before()).

It would be useful to have some option (--measure-before ?) to highlight tests that are above threshold together with appropriate before(Each)().

[tj]

yeah there's been some discussion about this, it's a bit of a tough call, I dont want to bloat mocha with a bunch more options, I think we should just come to a conclusion on what's expected. I'm a bit torn between the two personally, we could also clutter the output a bunch more and add both but that's pretty ugly

[Almad]

Well it depends on the testing pattern. Personaly mine is to have one assert per it, so I usually do some call in before() and then verify multiple expectations in multiple it()'s so I can see all failures at once.

Of course then, timing that omits before is pretty much useless to me.

[tj]

im leaning towards it being additive and we leave it at that for now, at least then there's the indication of what is causing the entire suite to bog down

[Almad]

cool

[tj]

dup of #419