windows: workaround kernel race condition

[jacobly0]

This was causing flaky CI failures.

Reproduced by running this program concurrently with CI workflows:

const std = @import("std");
pub fn main() !void {
    while (true) {
        var child: std.process.Child = .init(&.{"repro.exe"}, std.heap.page_allocator);
        _ = try child.spawnAndWait();
        const file = try std.fs.cwd().openFile("repro.exe", .{ .mode = .read_write });
        defer file.close();
    }
}

[andrewrk]

Interesting. I think this logic will be a nice candidate to add into the Io implementation of opening files on Windows to disambiguate between real access denied error and a kernel bug. That way the same fix doesn't have to go into everybody's application code.

[mlugg]

windows is a great platform with zero infuriating kernel bugs around basic filesystem usage 👍