UPSTREAM: wireguard: selftests: ensure non-addition of peers with failed precomputation

Ensure that peers with low order points are ignored, both in the case
where we already have a device private key and in the case where we do
not. This adds points that naturally give a zero output.

Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
(cherry picked from commit f9398acba6a4ae9cb98bfe4d56414d376eff8d57)
Bug: 152722841
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>
Change-Id: I76ee06a8c84b5dfc333981fe4f69ead816db2917