scripts: use option to change event count

Signed-off-by: Sébastien Boisvert <boisvert@anl.gov>
message_multiplexer: use decision maker to change timeout

Signed-off-by: Sébastien Boisvert <boisvert@anl.gov>
decision_maker: improve constant names

Signed-off-by: Sébastien Boisvert <boisvert@anl.gov>
decision_maker: use 0 nanoseconds for the minimum timeout value

Signed-off-by: Sébastien Boisvert <boisvert@anl.gov>
decision_maker: don't explore unknown values when there is a good alternative

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