x/sys/windows: drop deprecated usage of `syscall.Syscall` in windows package

[aisk]

There are some syscall.Syscall or syscall.Syscall6 in windows package, these function are marked as deprecated and should be replaced by syscall.SyscallN.

[gabyhelp]

Related Code Changes

• syscall: remove support for deprecated and move files

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[gopherbot]

Change https://go.dev/cl/695235 mentions this issue: windows: using SyscallN to replace deprecated Syscall functions

[mknyszek]

Thanks. In the future, for cleanups like this, you generally don't need to file an issue. You can just send a change.

[qmuntal]

Note that there is already an in-progress CL tackling this refactor: https://go-review.googlesource.com/c/sys/+/691715.

[aisk]

Sorry, I missed it. Closing this PR.