Add flaky test TODO

Author: tejasd

firebase-perf/src/test/java/com/google/firebase/perf/session/gauges/GaugeManagerTest.java

@@ -402,6 +402,7 @@ public void testGaugeCounterIsDecrementedWhenLogged() {
   }
 
   @Test
+  // TODO(b/394127311): Investigate flaky test.
   public void testDuplicateGaugeLoggingIsAvoided() {
     int priorGaugeCounter = GaugeCounter.count();
     PerfSession fakeSession = createTestSession(1);

firebase-perf/src/test/java/com/google/firebase/perf/transport/TransportManagerTest.java

@@ -219,6 +219,7 @@ public void invalidGaugeMetric_transportNotInitialized_notLoggedAfterInitializat
   }
 
   @Test
+  // TODO(b/394127311): Investigate flaky test.
   public void
       logMultipleEvents_transportNotInitialized_validEventsGetLoggedInOrderAfterInitialization() {
     initializeTransport(false);