torture: Make kvm-recheck-scf.sh tolerate qemu-cmd comments

The qemu-cmd file can contain comments that are not relevant to the
operation of kvm-recheck-scf.sh. This commit therefore strips these
comments before looking for timing information.

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

torture: Add scftorture to the rcutorture scripting

This commit updates the rcutorture scripting to include the new scftorture
torture-test module.

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