torture: Use mktemp instead of guessing at unique names

This commit drags the rcutorture scripting kicking and screaming into the
twenty-first century by making use of the BSD-derived mktemp command to
create temporary files and directories. In happy contrast to many of its
ill-behaved predecessors, mktemp seems to actually work reasonably reliably!

Signed-off-by: Paul E. McKenney <paulmck@kernel.org>

torture: Add config2csv.sh script to compare torture scenarios

This commit adds a config2csv.sh script that converts the specified
torture-test scenarios' Kconfig options and kernel-boot parameters to
.csv format. This allows easier comparison of scenarios when one fails
and another does not.

Signed-off-by: Paul E. McKenney <paulmck@kernel.org>