rcu: Update TREE05.boot to test normal synchronize_rcu()

Add extra parameters for rcutorture module. One is the "nfakewriters"
which is set -1. There will be created number of test-kthreads which
correspond to number of CPUs in a test system. Those threads randomly
invoke synchronize_rcu() call.

Apart of that "rcu_normal" is set to 1, because it is specifically for
a normal synchronize_rcu() testing, also a newly added parameter which
is "rcu_normal_wake_from_gp" is set to 1 also. That prevents interaction
with other callbacks in a system.

Reviewed-by: Paul E. McKenney <paulmck@kernel.org>
Signed-off-by: Uladzislau Rezki (Sony) <urezki@gmail.com>
Link: https://lore.kernel.org/r/20250227131613.52683-2-urezki@gmail.com
Signed-off-by: Boqun Feng <boqun.feng@gmail.com>

Author: urezki

tools/testing/selftests/rcutorture/configs/rcu/TREE05.boot

@@ -2,3 +2,9 @@ rcutree.gp_preinit_delay=3
 rcutree.gp_init_delay=3
 rcutree.gp_cleanup_delay=3
 rcupdate.rcu_self_test=1
+
+# This part is for synchronize_rcu() testing
+rcutorture.nfakewriters=-1
+rcutorture.gp_sync=1
+rcupdate.rcu_normal=1
+rcutree.rcu_normal_wake_from_gp=1