The stout helper `os::which` fails on Windows uncondtionally because it tries using the `which` command, which of course doesn't exist. An equivalent is powershell -c get-command -type application; however, we may also just want to implement this in C++.
Sadly, because this fails, a lot of test filters fail. For instance, none of the INTERNET tests run because they use os::which to check for ping before running ping to check for internet connectivity. Ping does exist, but it's "not found" which is incorrect, and misleading.