[sheriff] Disable flaky AppBannerManagerTest

This test is flakily crashing on test-n-phone:
https://ci.chromium.org/p/chrome/builders/ci/test-n-phone

Example failure:
https://ci.chromium.org/p/chrome/builders/ci/test-n-phone/10873

TBR=dominickn@chromium.org

Bug: 1062843
Change-Id: Icd4539aa98dc09e90ef45cfc7599c36647b5894e
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2341405Reviewed-by: Natalie Chouinard <chouinard@chromium.org>
Commit-Queue: Natalie Chouinard <chouinard@chromium.org>
Cr-Commit-Position: refs/heads/master@{#795597}

chrome/android/javatests/src/org/chromium/chrome/browser/banners/AppBannerManagerTest.java

@@ -39,6 +39,7 @@ import org.chromium.base.task.PostTask;
 import org.chromium.base.test.util.CommandLineFlags;
 import org.chromium.base.test.util.DisabledTest;
 import org.chromium.base.test.util.Feature;
+import org.chromium.base.test.util.FlakyTest;
 import org.chromium.chrome.R;
 import org.chromium.chrome.browser.ChromeActivity;
 import org.chromium.chrome.browser.ShortcutHelper;
@@ -535,6 +536,7 @@ public class AppBannerManagerTest {
     @Test
     @SmallTest
     @Feature({"AppBanners"})
+    @FlakyTest(message = "crbug.com/1062843")
     public void testModalNativeAppBannerCanBeTriggeredMultipleTimesCustomTab() throws Exception {
         mCustomTabActivityTestRule.startCustomTabActivityWithIntent(
                 CustomTabsTestUtils.createMinimalCustomTabIntent(