Update web-platform-tests expectations

[alancutter]

The failures for the polyfill have changed overnight, probably due to a new version of Firefox.
This patch updates the expectations using the formattedFailures output from #466.

[suzyh]

There seems to be a fair bit of churn here, I'm guessing due to a reordering of the expectations due to a sort? In order to understand what changes actually happened, I think it would be valuable to have separate commits for the reordering without changes and then the actual changes that occurred.

[alancutter]

All the tests in web-platform-tests/web-animations were restructured and renamed, this is the main cause of churn.

[suzyh]

So which changes in the expectations were due to Firefox updating?

[alancutter]

My mistake, the web-platform-tests submodule commit isn't updated in this patch. All changes here are due to Firefox and the formattedFailures sorting.
I agree there's a lot of churn here but I don't really want to hunt down an old version of Firefox to be able to separate these changes.

[suzyh]

OK, let's leave as is. LGTM.