Prove that reap is done correctly on port stop

Make sure that PMD is able to free all remaining mbufs connected with any of descriptors pending on port stop

The test is to verify that PMD is able to free mbufs involved in transmission in case if port stop occurs

1. Obtain the source Ethernet address

2. Adjust the traffic template

3. Prepare TEST_ETHDEV_INITIALIZED state

4. Enable Tx multi-segment offload if supported

5. Prepare TEST_ETHDEV_RX_SETUP_DONE state

6. Prepare TEST_ETHDEV_TX_SETUP_DONE state

7. Prepare TEST_ETHDEV_STARTED state

8. Set up a mempool (or multiple mempool instances)

9. Ensure that interface is UP on Tester side

10. Generate packets and send them in bursts

11. Prepare TEST_ETHDEV_STOPPED state

12. Make sure that all the objects within the mempool are free

Parameters:

template	Traffic template
multi_mempool	If TRUE, multiple mempools will be created for building mbuf chains from randomly sized segments pulled out of those pools provided that the feature is supported by the transmit datapath
update_refcnt	Pktmbuf reference counter toggle used to activate reap operation check with respect to packets which shall not be released upon a Tx burst or port stop
ring_size_multiplier	An integer multiplier of Tx ring size used to compute the number of packets

reap_on_stop