(maint) Support multiple targets again
(maint) Support multiple targets again

With pcp-broker 1.0, we removed the ability to address multiple targets.
Acceptance test code still relied on it, so that a run with more than
one agent configured would fail. Update the code to send individual
messages for each target so it works again.

puppetlabs/pxp-agent,puppetlabs/pxp-agent,puppetlabs/pxp-agent