Disable NewTabPageCustomizeDialogTest.All for flakiness

TBR=tiborg@chromium.org

Bug: 1066459
Change-Id: I02debf69279f12752a92c16c98b5b3ce57a36726
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2128712Reviewed-by: Dominique Fauteux-Chapleau <domfc@chromium.org>
Commit-Queue: Dominique Fauteux-Chapleau <domfc@chromium.org>
Cr-Commit-Position: refs/heads/master@{#754937}

chrome/test/data/webui/new_tab_page/new_tab_page_browsertest.js

@@ -59,7 +59,8 @@ var NewTabPageCustomizeDialogTest = class extends NewTabPageBrowserTest {
   }
 };
 
-TEST_F('NewTabPageCustomizeDialogTest', 'All', function() {
+// Disabled for flakiness, see https://crbug.com/1066459
+TEST_F('NewTabPageCustomizeDialogTest', 'DISABLED_All', function() {
   mocha.run();
 });