First, when a section update is stolen, the thread that acquires
the stolen update should remove the update from the update queue
before returning to mark it as completed and allow other threads
waiting on the update to continue. This fixes a deadlock issue
with section updates.
Fix incorrect decrease queue resize. Previously, it attempted
to resize the _increase_ queue, which is the wrong queue.
Use ALL_DIRECTIONS_BITSET for every decrease queue direction bitset
as decrease propagation cancellation due to neighbour values exceeding
the target decrease value cause some neighbour directions to not
be checked, which causes the final update grid to be incorrect.