device-drivers/rcu: add wrapper script for rcutorture test

One of the possible ways to test RCU is to use rcutorture kernel module.
The test requires that kernel configured with CONFIG_RCU_TORTURE_TEST.
It runs rcutorture module using particular options and then inspects
dmesg output for module's test results.
For more information, please read Linux Documentation: RCU/torture.txt

Signed-off-by: Alexey Kodanev <alexey.kodanev@oracle.com>