[PR] CircleCI Windows build
[PR] CircleCI Windows build

Summary:
ports the Windows build from appveyor to Circle. currently only runs the tool tests, since that's all we run in appveyor, and the runtests.sh tests fail, mainly due to \ vs / in paths in the expected output.

this also doesn't publish flow.exe to github releases yet, since appveyor still does that. i want to make sure this works for a bit and then drop appveyor.

Pull Request resolved: https://github.com/facebook/flow/pull/8256

Reviewed By: samwgoldman

Differential Revision: D19349065

Pulled By: mroch

fbshipit-source-id: d5386c74149fbdd8657a40aa0578e1e4b90a2cb1

mroch/flow,samwgoldman/flow,mroch/flow,facebook/flow,facebook/flow,samwgoldman/flow,samwgoldman/flow,mroch/flow,samwgoldman/flow,mroch/flow,facebook/flow,samwgoldman/flow,facebook/flow,facebook/flow,facebook/flow,mroch/flow,mroch/flow,samwgoldman/flow,mroch/flow,samwgoldman/flow,facebook/flow