This changes the run-pnacl-sz script to be more consistent
with the other targets.

BUG=https://code.google.com/p/nativeclient/issues/detail?id=4167
R=jvoung@chromium.org

Review URL: https://codereview.chromium.org/1232483003 .

Patch from Reed Kotler <reed.kotler@imgtec.com>.