Mark an ActivityThreadTest as flaky

Bug: 194242735
Test: Build
Change-Id: I2452db8523438de4d06c938c3c3fa1d8a9aa0f4e

core/tests/coretests/src/android/app/activity/ActivityThreadTest.java

@@ -286,6 +286,7 @@ public class ActivityThreadTest {
     }
 
     @Test
+    @FlakyTest(bugId = 194242735)
     public void testHandleActivityConfigurationChanged_EnsureUpdatesProcessedInOrder()
             throws Exception {
         final TestActivity activity = mActivityTestRule.launchActivity(new Intent());