Update web-platform-tests expectations.

The first 11 tests in Event-constructors.html were fixed in #2194; the
remaining failure is #2173. Node-normalize.html was fixed in #2221.
auto merge of #2294 : Ms2ger/servo/update-wpt, r=jdm

The first 11 tests in Event-constructors.html were fixed in #2194; the
remaining failure is #2173. Node-normalize.html was fixed in #2221.