disables CrSettingsSiteListTest.SiteList as it's flaky

BUG=929455
TEST=test only change

Change-Id: Iecf7c394f073c6cad59b70c59d78eea43bc44dd0
Reviewed-on: https://chromium-review.googlesource.com/c/1457209
Commit-Queue: Scott Violet <sky@chromium.org>
Commit-Queue: Demetrios Papadopoulos <dpapad@chromium.org>
Auto-Submit: Scott Violet <sky@chromium.org>
Reviewed-by: Demetrios Papadopoulos <dpapad@chromium.org>
Cr-Commit-Position: refs/heads/master@{#629851}

chrome/test/data/webui/settings/cr_settings_browsertest.js

@@ -1345,7 +1345,8 @@ CrSettingsSiteListTest.prototype = {
   ]),
 };
 
-TEST_F('CrSettingsSiteListTest', 'SiteList', function() {
+// TODO(crbug.com/929455): flaky, fix.
+TEST_F('CrSettingsSiteListTest', 'DISABLED_SiteList', function() {
   mocha.grep('SiteList').run();
 });