Can we use a Puppet filename that would only exist on a Swarming host instead? Or is there a Recipe API for this?

We could have puppet create a file that we check in the function instead, but that increases our puppet dependency instead of decreasing it.

This function was originally just a sanity check on users misusing cbuildbot locally. I'd prefer to remove it and instead depend on users having/not having the correct credentials to do whatever is relevant.

However, the method has been misused to control some testing since then and that would need to be cleaned up.

Perhaps it's better to remove this method. It's only used in a few places, most of which seem to be doing the wrong thing anyway.

I was mistaken, it DOES understand our GCE builders.