Remove FalkyTests entry for xmlhttprequest-responseXML-ensure-noscript.html

No longer flaky.
http://test-results.appspot.com/dashboards/flakiness_dashboard.html#tests=xmlhttprequest-responseXML-ensure-noscript.html

R=kouhei
BUG=402261

Review URL: https://codereview.chromium.org/584793002

git-svn-id: svn://svn.chromium.org/blink/trunk@182303 bbb929c8-8fbe-4397-9dbb-9b2b20218538