Disable BMO test SyncDoubleInstallationDifferentUserDisplayMode

Score of 563 on the flakiness dashboard. The CL disables the test on
every platform except Windows.
https://findit-for-me.appspot.com/p/chromium/flake-portal/flakes?flake_filter=test_type%3A%3Async_integration_tests

Bug: 1126404
Change-Id: I1cffbf8beb44f678c8d60eaecc8936e4ceb77816
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2409695
Commit-Queue: Victor Vianna <victorvianna@google.com>
Reviewed-by: Marc Treib <treib@chromium.org>
Cr-Commit-Position: refs/heads/master@{#806600}

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

@@ -231,8 +231,16 @@ IN_PROC_BROWSER_TEST_F(TwoClientWebAppsBMOSyncTest,
   EXPECT_EQ(GetRegistrar(GetProfile(1)).GetAppShortName(app_id), "Test name 2");
 }
 
+// Flaky, see crbug.com/1126404.
+#if defined(OS_MAC) || defined(OS_LINUX) || defined(OS_CHROMEOS)
+#define MAYBE_SyncDoubleInstallationDifferentUserDisplayMode \
+  DISABLED_SyncDoubleInstallationDifferentUserDisplayMode
+#else
+#define MAYBE_SyncDoubleInstallationDifferentUserDisplayMode \
+  SyncDoubleInstallationDifferentUserDisplayMode
+#endif
 IN_PROC_BROWSER_TEST_F(TwoClientWebAppsBMOSyncTest,
-                       SyncDoubleInstallationDifferentUserDisplayMode) {
+                       MAYBE_SyncDoubleInstallationDifferentUserDisplayMode) {
   ASSERT_TRUE(SetupSync());
   ASSERT_TRUE(AllProfilesHaveSameWebAppIds());