net:fcnal-test.sh failed on Focal with "RTNETLINK answers: Invalid argument" and other 7 failures

[Po-Hsu Lin]

This is not a regression but failures uncovered by fixing bug 2006391

With Focal 5.4.0-145.162, this test will fail with:

 # IPv4 ping
 # With VRF
 # SYSCTL: net.ipv4.raw_l3mdev_accept=1
 # TEST: ping local, VRF bind - VRF IP [FAIL]
 # TEST: ping local, device bind - ns-A IP [FAIL]

 # SYSCTL: net.ipv4.ping_group_range=0 2147483647
 # TEST: ping local, VRF bind - VRF IP [FAIL]
 # TEST: ping local, device bind - ns-A IP [FAIL]

 # SYSCTL: net.ipv4.ping_group_range=0 2147483647
 # SYSCTL: net.ipv4.raw_l3mdev_accept=1
 # TEST: ping out, vrf device+address bind - ns-B IPv6 LLA [FAIL]

 # IPv6 address binds
 # No VRF
 # TEST: TCP socket bind to out of scope local address - ns-A loopback IPv6 [FAIL]

 # With VRF
 # TEST: TCP socket bind to VRF address with device bind - VRF IPv6 [FAIL]

And finally interrupted with this test case:
 # Ping LLA with multiple interfaces
 # RTNETLINK answers: Invalid argument

Which came from this command:
$ sudo ip -netns - -6 addr add dev lo
RTNETLINK answers: Invalid argument