Pidigits has different execution time behaviors depending on the length of folder path

[skrynski]

I observed for the commit 2616d99 , that pidigits exhibits two different execution time behaviors, that can be observed here (first tab): https://docs.google.com/spreadsheets/d/1bAOZKPMFbWW7NCLRHQDoSmg4NOd2E1P9bkOIFcCp-FY/edit#gid=923483365

I was able pin down these two behaviors depending on the length of the path the custom-r folder is located.
In my particular case, running at /home/skrynski/rirAAA1234567/external/custom-r and shorter paths, benchmark exhibits behavior 2.
Past that size, for example /home/skrynski/rirAAA12345678/external/custom-r, it shows behavior 1.
I could reproduce this on prl5 and on my linux box, but not always on the benchmarking machine (where it seems to vary a bit more).