When adb client connects to adb server, or when lldb connects to
lldb server on Android device, IPv6 does not work (at least on
Windows it does not work).
For Android on Windows, each IPv6 failure (fallback-to-IPv4) wastes
2 seconds, and since this is called 5 times when attaching, LLDB
is wasting 10 seconds. This CL brings a big improvement to attach latency.