rcutorture: Print forward-progress test age upon failure

This commit prints the age of the forward-progress test in jiffies,
in order to allow better interpretation of the callback-invocation
histograms.

Signed-off-by: Paul E. McKenney <paulmck@linux.ibm.com>
This commit is contained in:
Paul E. McKenney 2018-10-04 10:54:22 -07:00
commit 73d665b141