session: remove pause all jobs when upgrading (#46234)

[ti-chi-bot]

This is an automated cherry-pick of #46234

What problem does this PR solve?

Issue Number: close #46228, close #46227

Problem Summary:

What is changed and how it works?

• remove pause all jobs when upgrading
• update TestUpgradeWithPauseDDL and add a comment.

Check List

Tests

• Unit test
• Integration test
• Manual test (add detailed scripts or steps below)
  Pass the issue's test.
• No code

Side effects

• Performance regression: Consumes more CPU
• Performance regression: Consumes more Memory
• Breaking backward compatibility

Documentation

• Affects user behaviors
• Contains syntax changes
• Contains variable changes
• Contains experimental features
• Changes MySQL compatibility

Release note

Please refer to Release Notes Language Style Guide to write a quality release note.

None

[ti-chi-bot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: Defined2014, hawkingrei

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• OWNERS [Defined2014,hawkingrei]

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[ti-chi-bot]

[LGTM Timeline notifier]

Timeline:

• 2023-09-12 07:18:34.775702564 +0000 UTC m=+340096.700258952: ☑️ agreed by hawkingrei.
• 2023-09-12 07:19:39.009736701 +0000 UTC m=+340160.934293095: ☑️ agreed by Defined2014.