ConntrackSocketTest#testIpv4ConntrackSocket always fail in cuttlefish
because it gets NullPointerException when accessing tupleOrig in
ConntrackMessage. tupleOrig can be null if it doesn't have source IP.
This situation happens when dumping the following conntrack entry:
vsoc_x86_64:/ # cat /proc/net/nf_conntrack
ipv4 2 unknown 2 570 src=0.0.0.0 dst=224.0.0.22 [UNREPLIED] \
src=224.0.0.22 dst=0.0.0.0 mark=0 secctx=u:object_r:unlabeled:s0 use=2
Bug: 280203901
Test: atest TetheringPrivilegedTests (on cuttlefish)
Change-Id: Iddc8cb390a4369190d535f4694e0e5fa4b6e590f
9dfbb45bb6