Speed up `freebsd-update IDS` by using IFS to split fields instead of
forking lots of processes to run echo|cut.  In one test this reduced
the CPU time from 980s to 134s and the wallclock time from 806s to
132s.

Submitted by:	Oleg Ginzburg
MFprojects/camlock r254905:
Introduce new function devstat_end_transaction_bio_bt(), adding new argument
to specify present time.  Use this function to move binuptime() out of lock,
substantially reducing lock congestion when slow timecounter is used.