All the dropped platforms either don't support raw sockets or the tests
pass sucessfully (e.g. ipv4.TestPacketConnReadWriteMulticastICMP on
solaris), so the tests can rely on being skipped due to
!nettest.SupportsRawSocket().
Also check for errNotImplemented to cover cases where functionality is
not available on windows.
Change-Id: Ic9107a7ca16e9d9faed4991e1148b493c646ea7d
Reviewed-on: https://go-review.googlesource.com/c/net/+/489155
Run-TryBot: Tobias Klauser <tobias.klauser@gmail.com>
Reviewed-by: Ian Lance Taylor <iant@google.com>
TryBot-Result: Gopher Robot <gobot@golang.org>
Reviewed-by: Dmitri Shuralyov <dmitshur@google.com>
Auto-Submit: Tobias Klauser <tobias.klauser@gmail.com>
