Report more detailed statistics about task stealing in task queue stats

Current task queue statistics do not report much detail on task stealing, just the number of attempts.

Information about basic occurrences (how many empty, how many contended, how many contended in a row, max contended accesses in a row) in the task queue, particularly about contended accesses, which seem to correlate strongly to performance, are very interesting to improve the stealing mechanism.

Another interesting metric is the amount of times the bias has been dropped