Test multi node dynamic network ci (#696)

Buildkite automation for multinode test.  This test is ignored by default because it requires a large cpu machine to run.

ci/test-large-network.sh

@@ -0,0 +1,8 @@
+#!/bin/bash -e
+
+here=$(dirname "$0")
+cd "$here"/..
+export RUST_BACKTRACE=1
+export RUST_LOG=multinode=info
+set -x
+exec cargo test --release test_multi_node_dynamic_network -- --ignored