internal/socket: update zoneCache on cache misses to cover appearing interfaces
internal/socket: update zoneCache on cache misses to cover appearing interfaces

Updates golang/go#28535

Change-Id: Id653b21b4d893cc8b6b9a74b129d1ce9b7e26a9f
Reviewed-on: https://go-review.googlesource.com/c/147739
Reviewed-by: Mikio Hara <7d2a5fb8aa07e3795b8006c20159dd02aea6b94f@gmail.com>
Run-TryBot: Mikio Hara <7d2a5fb8aa07e3795b8006c20159dd02aea6b94f@gmail.com>

golang/net