Disable DemoSetupArcSupportedTest.BackOnNetworkScreen it's flaky.

Bug: 1121422
Change-Id: Idb8b39ece8bf8dadc3a89503b7b9ac07c46a6823
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2373725
Auto-Submit: Fergal Daly <fergal@chromium.org>
Reviewed-by: Aga Wronska <agawronska@chromium.org>
Commit-Queue: Fergal Daly <fergal@chromium.org>
Cr-Commit-Position: refs/heads/master@{#801259}

chrome/browser/chromeos/login/demo_mode/demo_setup_browsertest.cc

@@ -1108,7 +1108,13 @@ IN_PROC_BROWSER_TEST_F(DemoSetupArcSupportedTest,
   EXPECT_TRUE(IsScreenShown(EulaView::kScreenId));
 }
 
-IN_PROC_BROWSER_TEST_F(DemoSetupArcSupportedTest, BackOnNetworkScreen) {
+// TODO(https://crbug.com/1121422): Flaky on ChromeOS ASAN.
+#if defined(OS_CHROMEOS)
+#define MAYBE_BackOnNetworkScreen DISABLED_BackOnNetworkScreen
+#else
+#define MAYBE_BackOnNetworkScreen BackOnNetworkScreen
+#endif
+IN_PROC_BROWSER_TEST_F(DemoSetupArcSupportedTest, MAYBE_BackOnNetworkScreen) {
   SimulateNetworkConnected();
   SkipToScreen(NetworkScreenView::kScreenId);