Re-enable TwoClientExtensionAppsSyncTest.StartWithDifferentApps

This test seems to have been disabled mostly due to the
TextInputServerCreate Windows error [1], which doesn't manifest anymore
(crbug.com/1123944). Let's try to re-enable it.

[1] https://logs.chromium.org/logs/chromium/buildbucket/cr-buildbucket.appspot.com/8883515428383041104/+/steps/sync_integration_tests__with_patch__on_Windows-10-15063/0/logs/Flaky_failure:_All__x2f_TwoClientExtensionAppsSyncTest.StartWithDifferentApps__x2f_WebApps__status_CRASH_SUCCESS_/0

Bug: 1069843
Change-Id: I9bce6dd03effd2128f9691e887ab68962c898ada
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2498485
Commit-Queue: Victor Vianna <victorvianna@google.com>
Commit-Queue: Maksim Moskvitin <mmoskvitin@google.com>
Auto-Submit: Victor Vianna <victorvianna@google.com>
Reviewed-by: Maksim Moskvitin <mmoskvitin@google.com>
Cr-Commit-Position: refs/heads/master@{#821265}

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

@@ -89,9 +89,7 @@ IN_PROC_BROWSER_TEST_F(TwoClientExtensionAppsSyncTest,
 // Install some apps on both clients, some on only one client, some on only the
 // other, and sync.  Both clients should end up with all apps, and the app and
 // page ordinals should be identical.
-// Disabled due to flake: https://crbug.com/1069843
-IN_PROC_BROWSER_TEST_F(TwoClientExtensionAppsSyncTest,
-                       DISABLED_StartWithDifferentApps) {
+IN_PROC_BROWSER_TEST_F(TwoClientExtensionAppsSyncTest, StartWithDifferentApps) {
   ASSERT_TRUE(SetupClients());
 
   int i = 0;