Improve message_bridge_test failure error

It isn't clear what went wrong sometimes.  Log more when the test fails.

Change-Id: Idacfb43c2a0fbe63270acd8195cbc177941ceca0
Signed-off-by: Austin Schuh <austin.linux@gmail.com>
diff --git a/aos/network/message_bridge_test.cc b/aos/network/message_bridge_test.cc
index 8222760..74d22c2 100644
--- a/aos/network/message_bridge_test.cc
+++ b/aos/network/message_bridge_test.cc
@@ -679,10 +679,12 @@
 
   // Make sure the offset in one direction is less than a second.
   EXPECT_GT(
-      client_statistics_fetcher->connections()->Get(0)->monotonic_offset(), 0);
+      client_statistics_fetcher->connections()->Get(0)->monotonic_offset(), 0)
+      << aos::FlatbufferToJson(client_statistics_fetcher.get());
   EXPECT_LT(
       client_statistics_fetcher->connections()->Get(0)->monotonic_offset(),
-      1000000000);
+      1000000000)
+      << aos::FlatbufferToJson(client_statistics_fetcher.get());
 
   EXPECT_GE(pi1_server_statistics_count, 2);
   EXPECT_GE(pi2_server_statistics_count, 2);