rcutorture: Update test scenarios based on new Kconfig dependencies

A number of the rcutorture test scenarios were not using the desired
Kconfig options because dependencies were preventing the selections in the
Kconfig-fragment files from being honored.  This commit therefore updates
the Kconfig-fragment files to account for these changes in dependencies.

Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>