net_test: fix sock_diag_test.py to handle ipv5 correctly

[ipv5 is ipv4 mapped ipv6]

af_inet6_socket.connect(('8.8.8.8', 53)) is bogus and should be
af_inet6_socket.connect(('::ffff:8.8.8.8', 53)) instead

Python's behaviour when passing an ipv4 literal to an ipv6 socket
has always been notoriously stupid: no error, just treat as ::.
Seems like newer python is even stupider: no error, just treat as garbage.

Bug: 74373492
Change-Id: I7c36236cd34246a2fff63864f81463ba2627841c