runtime: correct arguments to pipe2 syscall in pipe on netbsd/arm64

runtime: correct arguments to pipe2 syscall in pipe on netbsd/arm64

Follow the implementation of pipe2 to pass arguments and handle return
values.

With this fix the runtime tests pass on netbsd/arm64 (tested using
gomote on the netbsd-arm64-bsiegert builder).

Update #30824

Change-Id: I346db68fc9dde8dc7f11351af05c1ad3105f4a32
Reviewed-on: https://go-review.googlesource.com/c/go/+/258000
Trust: Tobias Klauser <tobias.klauser@gmail.com>
Trust: Benny Siegert <bsiegert@gmail.com>
Run-TryBot: Tobias Klauser <tobias.klauser@gmail.com>
Reviewed-by: Benny Siegert <bsiegert@gmail.com>
TryBot-Result: Go Bot <gobot@golang.org>