Helps and/or blocks until the given task is done or timeout.
First tries locally helping, then scans other queues for a task
produced by one of w's stealers; compensating and blocking if
none are found (rescanning if tryCompensate fails).
@param w caller
@param task the task
@param deadline for timed waits, if nonzero
@return task status on exit
Helps and/or blocks until the given task is done or timeout. First tries locally helping, then scans other queues for a task produced by one of w's stealers; compensating and blocking if none are found (rescanning if tryCompensate fails).
@param w caller @param task the task @param deadline for timed waits, if nonzero @return task status on exit