[android] Disable FeedNewTabPageTest.testFeedDisabledByPolicy

It seems to be flaky not only on earlier mentioned bots like
android-pie-x86-fyi-rel, but is also flaky on test-n-phone.

Bug: 1064388
Change-Id: I95ef0332b57897255b23eca86ddfd2bc351636b4
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2122463
Commit-Queue: Tommy Nyquist <nyquist@chromium.org>
Commit-Queue: John Budorick <jbudorick@chromium.org>
Auto-Submit: Tommy Nyquist <nyquist@chromium.org>
Reviewed-by: John Budorick <jbudorick@chromium.org>
Cr-Commit-Position: refs/heads/master@{#753735}

chrome/android/feed/core/javatests/src/org/chromium/chrome/browser/feed/FeedNewTabPageTest.java

@@ -293,6 +293,7 @@ import java.util.List;
     @Test
     @MediumTest
     @Feature({"FeedNewTabPage"})
+    @DisabledTest(message = "crbug.com/1064388")
     public void testFeedDisabledByPolicy() throws Exception {
         final boolean pref = TestThreadUtils.runOnUiThreadBlocking(
                 ()