Disable flaky WizardControllerDemoSetupDeviceDisabledTest.OnlineDemoSetup

TBR=alemate@chromium.org

Bug: 894384
Change-Id: I7b9f1f8cca3c0e65fa4818c0a79558533fb2edea
Reviewed-on: https://chromium-review.googlesource.com/c/1275851Reviewed-by: Vasilii Sukhanov <vasilii@chromium.org>
Commit-Queue: Vasilii Sukhanov <vasilii@chromium.org>
Cr-Commit-Position: refs/heads/master@{#598714}

chrome/browser/chromeos/login/wizard_controller_browsertest.cc

@@ -2393,8 +2393,9 @@ class WizardControllerDemoSetupDeviceDisabledTest
   DISALLOW_COPY_AND_ASSIGN(WizardControllerDemoSetupDeviceDisabledTest);
 };
 
+// Flaky https://crbug.com/894384.
 IN_PROC_BROWSER_TEST_F(WizardControllerDemoSetupDeviceDisabledTest,
-                       OnlineDemoSetup) {
+                       DISABLED_OnlineDemoSetup) {
   CheckCurrentScreen(OobeScreen::SCREEN_OOBE_WELCOME);
   EXPECT_FALSE(DemoSetupController::IsOobeDemoSetupFlowInProgress());
   WaitUntilJSIsReady();