Print the socket error when connect fails.

I suspect this won't actually tell us much useful w.r.t. the Mac test
flakes, but we may as well print what we can get.

Change-Id: I4931f6000648c4bd955a132b54351ff83d6b6273
Reviewed-on: https://boringssl-review.googlesource.com/17804
Commit-Queue: Steven Valdez <svaldez@google.com>
Reviewed-by: Steven Valdez <svaldez@google.com>
CQ-Verified: CQ bot account: commit-bot@chromium.org <commit-bot@chromium.org>

ssl/test/bssl_shim.cc

diff --git a/ssl/test/bssl_shim.cc b/ssl/test/bssl_shim.cc
index 777e2ee..cb9fdc9 100644
--- a/ssl/test/bssl_shim.cc
+++ b/ssl/test/bssl_shim.cc
@@ -1013,6 +1013,7 @@
     }
     closesocket(sock);
   }
+  PrintSocketError("connect");
   return -1;
 }