It's there now, it recently just got added because the script recently got released.
BTW here is the download link of the x264 bench
It will probably ask for AViSynth, an easy and quick download and install. Small file this one, no worries.
All you have to do is to save the txt file as a bat and replace your bat script that came with the x264 download. Now the test will loop until it's done 20 passes. There is a crazy 50 loop version a few pages ago but I find that excessive.
I found x264 just after I posted, but hadn't found the script yet. Thank you for the help! I'm off to test .