Run PTF test on real hardware

[Yi-Tseng]

We start seeing a different result between the Tofino model and the real hardware.
For example, switch(with fabric-spgw-int profile) sends packets with the same 5-tuple to different next-hops on the hardware switch, but in the PTF test with Tofino Model(FabricIPv4UnicastGroupTest*) pass since a while ago(no longer see the failure since end of 2020, see #98)

It is useful to run PTF tests with real hardware to make sure we got what we want.

[ccascone]

@Yi-Tseng do you know why we are not observing this behavior when running PTF-TV on the hardware switch? Could it be that the specific case you were observing on the hardware switch is not covered by PTF, e.g., the switch is processing packets that have different headers than the one used in PTF, such as SCTP from the eNB to the MME?

[Yi-Tseng]

fixed with PR #299