remote: use winio DialPipeContext for named pipes

[iankingori]

This PR fixes an issue where the Dialer in go does not support named pipes which the buildkit daemon on Windows uses. I've added a utility DialContext function that uses DialPipeContext for npipe connections on windows.

[jedevc]

Just a note: this seems similar to moby/buildkit#4127.

If DialContext doesn't support named pipes, then maybe the right call is to pull that upstream change in, and fix with that (it creates a connhelper for npipe).

Edit: ignore me, I saw #2286 (not quite sure why it was closed and replaced), and it was a bit clearer. Related but not the same - we explicitly choose to use DialContext in buildx, so we would need to explicitly use winio.DialPipeContext if we want that here.

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Future note - could you link between PRs/issues/etc when they're all related to make it a bit easier to navigate between - I hadn't quite realized this was connected to #2250 (comment).

[tonistiigi]

@iankingori Check the linter error and remove draft if ready.

[iankingori]

Thanks @jedevc, I'll drop some more context on the next one.

I'm creating an issue to track remote driver tests for windows

[iankingori]

The test failure looks like a flake, previous runs passed and only change since was a linting error.

[tianon-sso]

Can confirm this fixes the problem I had in #2250 (comment)!! Thanks all! 😄 ❤️

$ ~/git/buildx/buildx.exe --builder windows du
Reclaimable:    0B
Total:          0B