syscall: let errors.ErrUnsupported match ERROR_NOT_SUPPORTED and ERROR_CALL_NOT_IMPLE...

syscall: let errors.ErrUnsupported match ERROR_NOT_SUPPORTED and ERROR_CALL_NOT_IMPLEMENTED

These error codes are returned on windows in case a particular functions
is not supported.

Updates #41198

Change-Id: Ic31755a131d4e7c96961ba54f5bb51026fc7a563
Reviewed-on: https://go-review.googlesource.com/c/go/+/476916
Auto-Submit: Tobias Klauser <tobias.klauser@gmail.com>
Reviewed-by: Bryan Mills <bcmills@google.com>
Reviewed-by: Ian Lance Taylor <iant@google.com>
Run-TryBot: Tobias Klauser <tobias.klauser@gmail.com>
TryBot-Result: Gopher Robot <gobot@golang.org>