Add a test case to verify that BGP packets use queue7

[prabhataravind]

Description of PR

• Add a test case to verify that BGP packets use queue7 on all platforms
• All control packets including BGP are expected to use queue7, separate from data packet queues

Summary:
Fixes #7695

Type of change

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

Back port request

• 201911
• 202012
• 202205

Approach

What is the motivation for this PR?

It was observed that control packets use queue 0 in TD2 platforms which can lead to these packets being lost when link utilization becomes close to 100%. This can lead to critical issues in field like BGP keepalive failures. This management test is a way to make sure that this doesn't happen again in production.

How did you do it?

By bringing up BGP sessions with neighbors and making sure that BGP control traffic uses queue 7 by default using "show queue counters".

How did you verify/test it?

By running the test and making sure that it works as expected, reporting success or failure depending on which queues are used by control packets.

Any platform specific information?

This is applicable to all platforms.

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

Documentation

[mssonicbld]

The pre-commit check detected issues in the files touched by this pull request.
The pre-commit check is a mandatory check, please fix detected issues.

Detailed pre-commit check results:
trim trailing whitespace.................................................Passed
fix end of files.........................................................Passed
check yaml...........................................(no files to check)Skipped
check for added large files..............................................Passed
check python ast.........................................................Passed
flake8...................................................................Failed
- hook id: flake8
- exit code: 1

tests/bgp/test_bgp_queue.py:62:47: E231 missing whitespace after ','
tests/bgp/test_bgp_queue.py:64:47: E231 missing whitespace after ','

check conditional mark sort..........................(no files to check)Skipped

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sudo pip install pre-commit

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pre-commit install

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pre-commit run --from-ref <commit_id> --to-ref <commit_id>

[mssonicbld]

Cherry-pick PR to 202305: #9991

[wangxin]

@prabhataravind This is a new case. Generally, we only backport bug fixes to release branches. Can you elaborate why this PR is also required for 202205 and 202012 branch?

[prabhataravind]

@prabhataravind This is a new case. Generally, we only backport bug fixes to release branches. Can you elaborate why this PR is also required for 202205 and 202012 branch?

@wangxin, Neetha added request labels for these branches. I also think this is a good test case for all release branches.. BGP packets using another queue can potentially lead to unwanted BGP flaps in production. This was a repair item for an issue found in 201911 but also seen on 202012 and 202205 on certain bcm and cisco platforms..

[rlhui]

@wangxin , please help expediting the cherry-pick, thanks.

[mssonicbld]

Cherry-pick PR to 202012: #10641

[mssonicbld]

Cherry-pick PR to 202205: #10642

[Blueve]

@prabhataravind FYI, we need to skip this test case for some platforms that do not have QoS related feature supported