Rewrote the JSONValidator to support reruns

JSONValidator is now a Starcounter application, and takes no user input
during execution. Target file and action (accept or rerun) are specified
as command line arguments
Revert "Added a constructor of TestRunner that takes an internal test path"

This reverts commit de9911031712b97bf2af651f88831dbca1e8dd1d.
Changed JSONValidator to use old TestRunner constructor