[testgap] validate preserving copp tables work during in/cross-branch upgrades

[vaibhavhd]

Description
This is regarding sonic-net/SONiC#1107

The design added a change where COPP table is preserved for MLNX platforms.

With this new change a test gap has surfaced to ensure:
Fast and warm upgrade is not broken - in/cross-branch.
Cross branch upgrade has no issues (eg., 201911 -> 202205): copp table entries after upgrade are as expected. This is critical to ensure that there are no crashes, the entries from 201911 are deleted, entries from 202205 are as expected.
The keys and corresponding values are as expected in appl_db.
All traps from base OS are still functional on the target OS.

Steps to reproduce the issue:
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Describe the results you received:

Describe the results you expected:

Additional information you deem important:

**Output of `show version`:**

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**Attach debug file `sudo generate_dump`:**

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