rcutorture: Handle multiple runs of the same test

This commit fixes handling numbering of multiple runs of the same test
so as to disambiguate output.

Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>

diff --cc tools/testing/selftests/rcutorture/bin/kvm.sh
Simple merge