The windows build was still on the old plan from way back when where
we had binaries littered in the build tree and you had to add parts of
your build-tree to the `%PATH%` for the integration tests to work.
This cleans that up and moves all of our scripts that invoke
javascript to be on the same plan. They invoke our specially named
node with a relative path to the JS code we want to run.
We only have one AppVeyor worker and building topic branches causes us
to build large backups in our queues. This is made worse when folks
are iterating on a PR because each push queues not only a PR
build (which we want) but also the topic branch build (which we don't
care about so much).
