Revert "[Signin][Android] Re-enable FirstRunTest"

This reverts commit 9cad3c10.

Reason for revert: test still flaky
https://test-results.appspot.com/dashboards/flakiness_dashboard.html#testType=chrome_public_test_apk&tests=FirstRunTest

Original change's description:
> [Signin][Android] Re-enable FirstRunTest
>
> Enables FirstRunTest that was fixed in https://crrev.com/c/2450291.
> Enabling is done in a separate CL to simplify the revert in case these
> tests are still flaky.
>
> Bug: 616456
> Change-Id: I289ccf035a22835b38917680fd74fb8ce9b3e761
> Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2487104
> Commit-Queue: Boris Sazonov <bsazonov@chromium.org>
> Reviewed-by: Marc Treib <treib@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#818931}

TBR=treib@chromium.org,bsazonov@chromium.org

Change-Id: I568904663d59c88976e55285d30a2d9805a36b0e
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Bug: 616456
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2488343Reviewed-by: Gang Wu <gangwu@chromium.org>
Commit-Queue: Gang Wu <gangwu@chromium.org>
Cr-Commit-Position: refs/heads/master@{#819120}

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

@@ -22,6 +22,7 @@ import org.junit.runner.RunWith;
 
 import org.chromium.base.CommandLine;
 import org.chromium.base.test.util.CallbackHelper;
+import org.chromium.base.test.util.DisabledTest;
 import org.chromium.base.test.util.Feature;
 import org.chromium.chrome.browser.SyncFirstSetupCompleteSource;
 import org.chromium.chrome.browser.document.ChromeLauncherActivity;
@@ -113,6 +114,7 @@ public class FirstRunTest {
     @Test
     @LargeTest
     @Feature({"Sync"})
+    @DisabledTest(message = "https://crbug.com/616456")
     public void testSignIn() {
         Account testAccount = mSyncTestRule.addTestAccount();
         Assert.assertNull(mSyncTestRule.getCurrentSignedInAccount());
@@ -128,6 +130,7 @@ public class FirstRunTest {
     @Test
     @LargeTest
     @Feature({"Sync"})
+    @DisabledTest(message = "https://crbug.com/616456")
     public void testSignInWithOpenSettings() {
         final Account testAccount = mSyncTestRule.addTestAccount();
         final SettingsActivity settingsActivity =
@@ -160,6 +163,7 @@ public class FirstRunTest {
     @Test
     @LargeTest
     @Feature({"Sync"})
+    @DisabledTest(message = "https://crbug.com/616456")
     public void testNoSignIn() {
         mSyncTestRule.addTestAccount();
         Assert.assertFalse(SyncTestUtil.isSyncRequested());