rcutorture: Add a test for synchronize_rcu_mult()

This commit adds a crude test for synchronize_rcu_mult().  This is
currently a smoke test rather than a high-quality stress test.

Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
This commit is contained in:
Paul E. McKenney 2020-03-06 14:00:46 -08:00
commit 9cf8fc6fab