Fixes#4647
It seems that Windows creates a link-local address for the TUN driver, seemingly
based on the (fixed) adapter GUID. This results in a fixed MAC address, which
for some reason doesn't handle loopback correctly. Given the derived link-local
address is preferred for lookups (thanks LLMNR), traffic which addresses the
current node by hostname uses this broken address and never works.
To address this, we remove the broken link-local address from the wintun adapter.
Signed-off-by: Tom DNetto <tom@tailscale.com>
2903d42921