Remove a harmless(?) debugging print() from a test.
Avoid uninitialized value warnings when testing in development.
Speed up a test by adding an idle event to POE::Wheel::FollowTail.

Rather than wait for several seconds to elapse, tests can set a low
PollInterval and use IdleEvent handlers to tell when it's ready to
move on.

As a proof of concept, this commit also removes about 8 seconds from a
regression test using the new IdleEvent.