Mutex profiling stats

http://obsecurity.dyndns.org/mutex/

This has the full mutex profiling traces for 

* simultaneous extraction of 12 large tarballs on 4 CPU amd64 to md

* buildworld -j8 on SCSI disks

One really cool thing about the buildworld trace is that total Giant
acquisitions only come to about #90 in the overall ranking of total
mutexes acquired (2166754 Giant acquisitions total - and it would be
about half that if I wasn't using a SCSI disk).

Kris