Flakiness dashboard: simplify logic around which tests to show.
https://bugs.webkit.org/show_bug.cgi?id=113250

Reviewed by Ojan Vafai.

The different filters for showing results are only used for layout
tests, otherwise, we show everything.

Change the defaults to false (what layout tests used), and only
look at the values when viewing layout tests.

* TestResultServer/static-dashboards/flakiness_dashboard.js:
(htmlForTestsWithExpectationsButNoFailures):
(shouldHideTest):


git-svn-id: http://svn.webkit.org/repository/webkit/trunk@146926 268f45cc-cd09-0410-ab3c-d52691b4dbfc