[Android] Disable flaky tests in BookmarksTest

Disables testDisabledNoDownloadBookmark and testDisabledNoUploadBookmark
tests as they are flaky.
Failed builder link:
https://ci.chromium.org/p/chromium/builders/ci/Marshmallow%20Tablet%20Tester/13072.

TBR=treib@chromium.org

Bug: 964342
Change-Id: I88d188a9933ddade6bcd8e607af7b08af524bba0
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1617765Reviewed-by: Boris Sazonov <bsazonov@chromium.org>
Commit-Queue: Boris Sazonov <bsazonov@chromium.org>
Cr-Commit-Position: refs/heads/master@{#660895}

chrome/android/javatests/src/org/chromium/chrome/browser/sync/BookmarksTest.java

@@ -16,6 +16,7 @@ import org.junit.Test;
 import org.junit.runner.RunWith;
 
 import org.chromium.base.test.util.CommandLineFlags;
+import org.chromium.base.test.util.DisabledTest;
 import org.chromium.base.test.util.Feature;
 import org.chromium.chrome.browser.ChromeSwitches;
 import org.chromium.chrome.browser.bookmarks.BookmarkBridge;
@@ -384,6 +385,7 @@ public class BookmarksTest {
     @Test
     @LargeTest
     @Feature({"Sync"})
+    @DisabledTest(message = "https://crbug.com/964342")
     public void testDisabledNoDownloadBookmark() throws Exception {
         mSyncTestRule.disableDataType(ModelType.BOOKMARKS);
         addServerBookmark(TITLE, URL);
@@ -395,6 +397,7 @@ public class BookmarksTest {
     @Test
     @LargeTest
     @Feature({"Sync"})
+    @DisabledTest(message = "https://crbug.com/964342")
     public void testDisabledNoUploadBookmark() throws Exception {
         mSyncTestRule.disableDataType(ModelType.BOOKMARKS);
         addClientBookmark(TITLE, URL);