rcutorture: Make rcutorture support srcu double call test

This commit allows rcutorture to test double-call_srcu() when the
CONFIG_DEBUG_OBJECTS_RCU_HEAD Kconfig option is enabled.  The non-raw
sdp structure's ->spinlock will be acquired in call_srcu(), hence this
commit also removes the current IRQ and preemption disabling so as to
avoid lockdep complaints.

Link: https://lore.kernel.org/all/20240407112714.24460-1-qiang.zhang1211@gmail.com/



Signed-off-by: Zqiang <qiang.zhang1211@gmail.com>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>