torture: Enable DEBUG_OBJECTS_RCU_HEAD for Tiny RCU

The RCU torture tests currently do not run any Tiny RCU scenarios for
CONFIG_DEBUG_OBJECTS_RCU_HEAD=y.  This is a hole in the test, given
that someone might need this in real life and given that Tiny RCU uses
different callback-handling code than does Tree RCU.  This commit
therefore enables this Kconfig option for scenario TINY02.

Reported-by: "Ahmed, Iftekhar" <ahmedi@oregonstate.edu>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>