Improve log readability of test output

[RyanCavanaugh]

Today when a Travis build fails, e.g. https://travis-ci.org/DefinitelyTyped/DefinitelyTyped/builds/362263112?utm_source=github_status&utm_medium=notification , the actual error introduced by the change can be extremely low in the file (in the linked one, it's around line 4,800).

Ideally we would just not have quite so much log spam (all the "duplicate" notifications, for example, are useless) and the error could be up top. If there's actual diagnostic value in some of them, though, there appears to be log folding support: travis-ci/travis-ci#2285

I think the general goal should be that we can see the relevant error text without scrolling down more than a screenful on the Travis webpage - DT authors will probably at least scroll down this far and realize what they've broken

[mhegazy]

#449 removes the <package> OK line.