[Sheriff] Disable TwoClientPreferencesSyncTest.Sanity_E2ETest.

Disable TwoClientPreferencesSyncTest.Sanity_E2ETest because flaky.

TBR=mastiz@chromium.org

Bug: 988404
Change-Id: I19c4fcffdf71fdea48eb8e35cf55f81aaa841386
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1729074Reviewed-by: vitaliii <vitaliii@chromium.org>
Commit-Queue: vitaliii <vitaliii@chromium.org>
Cr-Commit-Position: refs/heads/master@{#682703}

chrome/browser/sync/test/integration/two_client_preferences_sync_test.cc

@@ -44,7 +44,9 @@ class TwoClientPreferencesSyncTest : public SyncTest {
   DISALLOW_COPY_AND_ASSIGN(TwoClientPreferencesSyncTest);
 };
 
-IN_PROC_BROWSER_TEST_F(TwoClientPreferencesSyncTest, E2E_ENABLED(Sanity)) {
+// TODO(crbug.com/988404): Enable once not flaky anymore.
+IN_PROC_BROWSER_TEST_F(TwoClientPreferencesSyncTest,
+                       E2E_ENABLED(DISABLED_Sanity)) {
   DisableVerifier();
   ASSERT_TRUE(SetupSync()) << "SetupSync() failed.";
   // Wait until sync settles before we override the prefs below.