tcp: don't allow to connect a TCP/IPv6 endpoint in TIME WAIT state

This ensures the TCP/IPv4 and TCP/IPv6 behave the same.

Reported by: syzbot+4de353ba85dac4dcb1ab@syzkaller.appspotmail.com
Reviewed by: Peter Lei
MFC after: 1 week
Sponsored by: Netflix, Inc.
Differential Revision: https://reviews.freebsd.org/D51125