Revert "Use only 2 queued work arrays in avalon."

This reverts commit 0ea9d68d6786473b641bc377651b908aeeab06a2.

This was leading to failure to find work items on block changes.
The result_wrong measurement for avalon is continually leading to false positives so remove it.
select() on serial usb in avalon does not work properly with zero timeout.