(PUP-3277) Use single quotes for cve injection test file content

Made a mistake adjusting cve-2013-4761_injection_of_class_names_loading_code
by double quoting the site.pp content in the manifest; on some (all?) platforms
the variable was interpolated by the shell and vanished. Changing to
single quotes allows the test to run properly. Change to he ci-rerun-pe
helper script is just to more closely match pe acceptance three node layout.