[action] [PR:16005] ip/test_ip_packet.py Increase tx_ok tolerance from 200 to 400 on T2

[mssonicbld]

#7954 described an issue we saw on T2 platforms where test_ip_packet.py::test_forward_ip_packet_with_0xffff_chksum_drop would fail sporadically if sufficient control/background traffic egressed the out_ifaces.

#8414 was created to fix this by increasing the tolerance from 100 to 200 packets. However, it seems like this wasn't sufficient tolerance as we're seeing failures on T2 devices:

Failed: Forwarded 276 packets in tx, not in expected range
Failed: Forwarded 275 packets in tx, not in expected range
Failed: Forwarded 264 packets in tx, not in expected range
Failed: Forwarded 295 packets in tx, not in expected range
Failed: Forwarded 316 packets in tx, not in expected range
Failed: Forwarded 301 packets in tx, not in expected range
Failed: Forwarded 264 packets in tx, not in expected range

But if we look at the RX_DROP counters we see all 1000 packets were dropped on RX:

root@cmp235-3:~# show interfaces counters
Last cached time was 2024-12-10T22:16:35.704269
 IFACE STATE RX_OK RX_BPS RX_UTIL RX_ERR RX_DRP
----------- ------- ------- ---------- --------- -------- --------
Ethernet144 U 15,399 141.74 B/s 0.00% 0 1,000

So the packets captured on TX was background traffic.

Summary:
Fixes #7954

Type of change

• Bug fix
• Testbed and Framework(new/improvement)
• Test case(new/improvement)

Back port request

• 202012
• 202205
• 202305
• 202311
• 202405

[mssonicbld]

/azp run

[mssonicbld]

Original PR: #16005

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