Disable flaky SyncTest

This CL disables the following test:

* org.chromium.chrome.browser.sync.SyncTest#testSignInAndOut

Because it's flaky on builder:

* android-arm-beta-tests

TBR=yfriedman@chromium.org

Bug: 1144221
Change-Id: I18fb396a0f54a5f2e351245a66b6c592b7b9e820
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2510611Reviewed-by: Salvador Guerrero <salg@google.com>
Commit-Queue: Salvador Guerrero <salg@google.com>
Cr-Commit-Position: refs/heads/master@{#822728}

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

@@ -47,6 +47,7 @@ public class SyncTest {
     @Test
     @LargeTest
     @Feature({"Sync"})
+    @DisabledTest(message = "crbug.com/1144221")
     public void testSignInAndOut() {
         Account account = mSyncTestRule.setUpAccountAndEnableSyncForTesting();