thorium: update multiplexer timeout

Signed-off-by: Sébastien Boisvert <boisvert@anl.gov>
scripts: update latency_probe invocation script

Signed-off-by: Sébastien Boisvert <boisvert@anl.gov>
message_multiplexer: use virtual topology for aggregation

Signed-off-by: Sébastien Boisvert <boisvert@anl.gov>