Make test.py run the most recently built binary

With this, running test.py auto-selects whatever binary has the latest mtime and runs it.  Only really tested with Python 2.7 Mac/Windows, but I think it'll work...

Glob wasn't doing what I wanted for some reason on Windows, but that's fine since Windows generally always builds in the same dir anyway.

Apparently the icache test is generating an unknown syscall... who knew?

-[Unknown]