Tests: move logging out of alarm.

Logging large amounts of data may be terminated by alarm() which isn't
really good (and likely to corrupt TAP output).  Problem seen on limit_req.t
test with logging enabled.
diff --git a/lib/Test/Nginx.pm b/lib/Test/Nginx.pm
index 7318322..16af7b4 100644
--- a/lib/Test/Nginx.pm
+++ b/lib/Test/Nginx.pm
@@ -366,13 +366,14 @@
 		select undef, undef, undef, $extra{sleep} if $extra{sleep};
 		return '' if $extra{aborted};
 		$reply = $s->getline();
-		log_in($reply);
 		alarm(0);
 	};
 	alarm(0);
 	if ($@) {
 		log_in("died: $@");
 		return undef;
+	} else {
+		log_in($reply);
 	}
 	return $reply;
 }