POE::Component::Pool::Thread threshold test broken

[scott]

The entire test suite was previously broken, but now I've unbroken most of the tests. The majority of the issue was that each of the tests had race conditions and wasn't using the test suite in "threadsafe" mode (which requires threads.pm to be loaded prior to Test::Simple/Test::Builder being loaded).

Most of these were fixed in a recent changeset.

The test suite is chock full of race conditions. It seems I had no idea what I was doing when writing it.