3node suites which perform encapsulation are increasing packet sizes, so the usual "${get_framesize} < ${1522}" does not work anymore. This is a typical copypaste error [0], which could be eliminated if parts of suite test template were generated by a script. Implement such a script.

[0] https://gerrit.fd.io/r/#/c/13411/21/tests/vpp/perf/srv6/10ge2p1x520-ethip6ip6-ip6base-srv6enc1sid-ndrpdr.robot@104