[DT2] Enhance everflow test on LT2/FT2 topology

[bingwang-ms]

Description of PR

Summary:
This PR is to enhance everflow test to support LT2/FT2 topology.

Type of change

• Bug fix
• Testbed and Framework(new/improvement)
• New Test case
  • Skipped for non-supported platforms
• Test case improvement

Back port request

• 202205
• 202305
• 202311
• 202405
• 202411
• 202505

Approach

What is the motivation for this PR?

This PR is to enhance everflow test to support LT2/FT2 topology.

How did you do it?

1. Update neighbor dictionary for LT2/FT2 topology.
2. Update port selection for LT2/FT2

How did you verify/test it?

The change is verified on a physical testbe.

collected 24 items                                                                                                                                                                                                            

everflow/test_everflow_testbed.py::TestEverflowV4IngressAclIngressMirror::test_everflow_basic_forwarding[erspan_ipv4-cli-downstream-default] SKIPPED (Skipping DOWN_STREAM test on FT2 topology.)                       [  4%]
everflow/test_everflow_testbed.py::TestEverflowV4IngressAclIngressMirror::test_everflow_neighbor_mac_change[erspan_ipv4-cli-downstream-default] SKIPPED (Skipping DOWN_STREAM test on FT2 topology.)                    [  8%]
everflow/test_everflow_testbed.py::TestEverflowV4IngressAclIngressMirror::test_everflow_remove_unused_ecmp_next_hop[erspan_ipv4-cli-downstream-default] SKIPPED (Skipping DOWN_STREAM test on FT2 topology.)            [ 12%]
everflow/test_everflow_testbed.py::TestEverflowV4IngressAclIngressMirror::test_everflow_remove_used_ecmp_next_hop[erspan_ipv4-cli-downstream-default] SKIPPED (Skipping DOWN_STREAM test on FT2 topology.)              [ 16%]
everflow/test_everflow_testbed.py::TestEverflowV4IngressAclIngressMirror::test_everflow_dscp_with_policer[erspan_ipv4-cli-downstream-default] SKIPPED (Skipping test since mirror with policer is not supported on Cisco 8000 platforms and Broadcom DNX platforms.) [ 20%]
everflow/test_everflow_testbed.py::TestEverflowV4IngressAclIngressMirror::test_everflow_frwd_with_bkg_trf[erspan_ipv4-cli-downstream-default] SKIPPED (Skipping DOWN_STREAM test on FT2 topology.)                      [ 25%]
everflow/test_everflow_testbed.py::TestEverflowV4IngressAclIngressMirror::test_everflow_basic_forwarding[erspan_ipv4-cli-upstream-default]  ^HPASSED                                                                       [ 29%]
everflow/test_everflow_testbed.py::TestEverflowV4IngressAclIngressMirror::test_everflow_neighbor_mac_change[erspan_ipv4-cli-upstream-default] PASSED                                                                    [ 33%]
everflow/test_everflow_testbed.py::TestEverflowV4IngressAclIngressMirror::test_everflow_remove_unused_ecmp_next_hop[erspan_ipv4-cli-upstream-default] 

Any platform specific information?

No.

Supported testbed topology if it's a new test case?

Not a new test.

Documentation

[mssonicbld]

/azp run

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Azure Pipelines successfully started running 1 pipeline(s).

[mssonicbld]

/azp run

[bingwang-ms]

CSP CS00012412189