Use a half nonce range before cycling through avalon's scanwork to ensure it gets a chance to fill work if time is tight for the write thread to signal a wakeup.
Revert "Sleep for less time in wait_avalon_ready till we have a better signalling system from read thread to write."

This reverts commit 98862b4f46b801e14b9474fdac4286145cbdf6b6.
Minimise the sleep times in avalon read to avoid result loss.