GTPUhw jumbo has zero traffic due to tx_errors

[vrpolakatcisco]

This become active after #4117 fix. See [0] for show hardware verbose output. That runs also contains GTPUsw test for comparison, which has no issue sending the GTPU-encapsulated jumbo packet without any important difference in packet trace [1].

[0] https://logs.fd.io/vex-yul-rot-jenkins-1/csit-vpp-perf-verify-3n-icx/19929387681/log.html.gz#s1-s1-s1-s1-s1-t1-k3-k1-k1-k1-k1-k8-k14-k1-k1-k1-k1
[1] https://logs.fd.io/vex-yul-rot-jenkins-1/csit-vpp-perf-verify-3n-icx/19929387681/log.html.gz#s1-s1-s1-s1-s1-t1-k3-k1-k1-k1-k1-k8-k14-k2-k1-k1-k1-k1