syscall: regenerate zsyscall_windows.go

syscall: regenerate zsyscall_windows.go

This CL regenerates zsyscall_windows.go, which was incorrectly
hand-edited in CL 463842.

Change-Id: Id556e69a282b2291a0b293b276ed4b9e0aeec105
Reviewed-on: https://go-review.googlesource.com/c/go/+/463848
TryBot-Result: Gopher Robot <gobot@golang.org>
Reviewed-by: Michael Knyszek <mknyszek@google.com>
Auto-Submit: Quim Muntal <quimmuntal@gmail.com>
Reviewed-by: Bryan Mills <bcmills@google.com>
Auto-Submit: Bryan Mills <bcmills@google.com>
Run-TryBot: Bryan Mills <bcmills@google.com>