torture: Make kvm-test-1-run-batch.sh select per-scenario affinity masks

This commit causes kvm-test-1-run-batch.sh to use the new
kvm-assign-cpus.sh and kvm-get-cpus-script.sh scripts to create a
TORTURE_AFFINITY environment variable containing either an empty string
(for no affinity) or a list of CPUs to pin the scenario's vCPUs to.
The additional change to kvm-test-1-run.sh places the per-scenario
number-of-CPUs information where it can easily be found.

If there is some reason why affinity cannot be supplied, this commit
prints and logs the reason via changes to kvm-again.sh.

Finally, this commit updates the kvm-remote.sh script to copy the
qemu-affinity output files back to the host system.

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