Fix flaky ReloadMappedListeners test by disabling blackhole detection as that code involves two interleaving QuicClients on the same thread and is thus unrealistically stringent.

Tested with:
rabbit test --config=tsan --target_environment=//buildenv/target:prod --test_filter=EndToEndTests/EndToEndTest.ReloadMappedListeners/Q050udp --test_sharding_strategy=disabled --runs_per_test=10000 //gfe/gfe2/quic:end_to_end_test
http://sponge2/057e4bea-8f49-4022-b107-ac21f6c8735b

Also remove one QuicStackTrace call. QuicStackTrace can take more than 30 seconds under tsan mode (as an example b/38200726) and thus is better used only together with QUIC_BUG.

PiperOrigin-RevId: 340336779
Change-Id: I8e938df28c2fb91cbb5e216736b1f51fa647d551

quic/test_tools/quic_test_client.cc

diff --git a/quic/test_tools/quic_test_client.cc b/quic/test_tools/quic_test_client.cc
index 8896cac..d7f2033 100644
--- a/quic/test_tools/quic_test_client.cc
+++ b/quic/test_tools/quic_test_client.cc
@@ -702,8 +702,7 @@
     epoll_server()->set_timeout_in_us(old_timeout_us);
   }
   if (trigger && !trigger()) {
-    QUIC_VLOG(1) << "Client WaitUntil returning with trigger returning false."
-                 << QuicStackTrace();
+    QUIC_VLOG(1) << "Client WaitUntil returning with trigger returning false.";
     return false;
   }
   return true;