Default enable 5rto blackhole detection. protected by gfe2_reloadable_flag_quic_default_enable_5rto_blackhole_detection.

PiperOrigin-RevId: 315016049
Change-Id: I4dfb1383bbd947c96192477c83daeb6c5b89aabf
diff --git a/quic/test_tools/quic_test_client.cc b/quic/test_tools/quic_test_client.cc
index ecab4bf..1b8abdd 100644
--- a/quic/test_tools/quic_test_client.cc
+++ b/quic/test_tools/quic_test_client.cc
@@ -957,7 +957,7 @@
   const QuicClock* clock = client()->client_session()->connection()->clock();
 
   QuicTime wait_until = clock->ApproximateNow() + kWaitDuration;
-  while (clock->ApproximateNow() < wait_until) {
+  while (connected() && clock->ApproximateNow() < wait_until) {
     // This waits for up to 50 ms.
     client()->WaitForEvents();
   }