Fix affinity in test script

Fix affinity in test script

You need to change the script!!!  See patch below.  All prior results
with more than 32 CPUs are bogus because the -a arguments confined the
threads to only 32 CPUs (the even-numbered ones from zero to 62).

Allow 64 CPUs.  Really needs to do the calculation based on the
stride and the number of CPUs, but a quick hack for now.

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