[cherry-pick] [PR:7781] Fix for PID assertion issue - PSUD and CHASSID platform cases (#7781)

[sanjair-git]

Cherry-Pick PR #7781 : For resolving conflicts.
Fix for PID assertion issue - PSUD and CHASSID platform cases.

Description of PR

Fixing up other chassisd and psud platform tests to poll for deamon to restart with bigger pid than before.
This is an extension of PR #7150.

Summary:
Fixes # (issue)

Fixes PSUD 'stop & start', 'term & start' and 'kill & start' test cases by making sure the daemon restarted has bigger PID than before.
Fixes CHASSID 'stop & start' and 'kill & start' test cases by making sure the daemon restarted has bigger PID than before.

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?

• Currently PSUD and CHASSID platform test cases like 'term & start', 'kill & start' and 'stop & start' don't check if the restarted daemon has bigger pid than the previous one or not.
• Currently "check_expected_daemon_status" doesn't verify about pre-daemon-pid, just returns TRUE even if the status is RUNNING with old PID.

How did you do it?

• By invoking 'check_if_daemon_restarted' method on the above-mentioned cases and making sure the new pid is bigger than the old pid.

How did you verify/test it?

• Ran the respective platform tests against a multi-asic line card in a T2 chassis.

Any platform specific information?

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

Documentation