rcutorture: Add CONFIG_PREEMPT_DYNAMIC=n to TASKS02 scenario

Now that CONFIG_PREEMPT_DYNAMIC=y is the default, TASKS02 no longer
builds a pure non-preemptible kernel that uses Tiny RCU.  This commit
therefore fixes this new hole in rcutorture testing by adding
CONFIG_PREEMPT_DYNAMIC=n to the TASKS02 rcutorture scenario.

Signed-off-by: Paul E. McKenney <paulmck@kernel.org>