rcutorture: Make preemptible TRACE02 enable lockdep

Currently, the CONFIG_PREEMPT_NONE=y rcutorture TRACE01 rcutorture
scenario enables lockdep.  This limits its ability to find bugs due to
non-preemptible sections of code being RCU readers, and pretty much all
code thus appearing to lockdep to be an RCU reader.  This commit therefore
moves lockdep testing to the CONFIG_PREEMPT=y rcutorture TRACE02 scenario.

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