tests: ensure run-unit-tests.sh returns a proper error code when tests fail

Signed-off-by: George K. Thiruvathukal <gkt@cs.luc.edu>
thorium_worker: compute latency in real time

Signed-off-by: Sébastien Boisvert <boisvert@anl.gov>
message_multiplexer: add a few debugging statements

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