Windows Graal native image support

[reibitto]

I gave this a try too, but ran into these blockers:
oracle/graal#1870
oracle/graal#1327

The next release looks like it'll include the fix. But even if you get passed that one, there might be other blockers lurking. Can't know until we try.

Also, Windows support for native-image seems very experimental right now. Just configuring everything was a huge pain for me. We might want to hold off on this issue until the Windows support is more stable. But if anybody wants to try tackling it anyway, that's fine with me.