Remove Tip note in text-transform/ tests

[dpino]

Fixes #13505.

The PR removes the Tip note entirely in all the text-transform/ tests that include such note. As commented, in #13505 there might be a part of the tip that is relevant. I can reintroduce it if it's valuable. I think in case that part of the tip needs to be rephrased.

In addition, the PR removes some extra whitespace in the html tag of many tests.

[frivoal]

Looks good to me, approved.

However, I'm not sure why the travis task failed when testing stability on firefox. I've restarted it for now, but if it keeps on failing we'll have to look into it.

[frivoal]

Still failing. Looks like an infrastructure problem to me, but I'm not sure.
@gsnedders @foolip @Ms2ger Any idea how to interpret this failure (and what to do about it)? https://travis-ci.org/web-platform-tests/wpt/jobs/441391903

[sideshowbarker]

Still failing. Looks like an infrastructure problem to me, but I'm not sure.
@gsnedders @foolip @Ms2ger Any idea how to interpret this failure (and what to do about it)? https://travis-ci.org/web-platform-tests/wpt/jobs/441391903

Raised #13513

[foolip]

Thanks for reporting! Let me admin merge this, it's still possible to investigate by creating an equivalent PR from the same point in history.

[r12a]

See my comment at #13505 (comment)