TC_pdp46_clients_interact GGSN_Tests_v4v6_only

Failing for the past 14 builds since #3188

Took 6 sec (from osmo-ttcn3-hacks_ggsn_tests)

Stack Trace

"GGSN_Tests.ttcn:982 : Timeout waiting for ICMPv6: { echoRequest := { typeField := 128, code := 0, checksum := ?, identifier := ?, sequenceNr := ?, data := ? } }"
      GGSN_Tests.ttcn:2456 GGSN_Tests control part
      GGSN_Tests.ttcn:1907 TC_pdp46_clients_interact testcase