PageStorage: background version compact for v2 (#6446)

[ti-chi-bot]

This is an automated cherry-pick of #6446

What problem does this PR solve?

Issue Number: close #6407

Problem Summary:
In the previous version, PageStorage v2 do the in-memory version list compaction when snapshot is released. Because multiple snapshot could be released concurrently, this causes some redundant CPU/memory resources.
What's more, slow-releasing snapshots cause DeltaTree's delta-compact task running slowly. This leads to many ColumnFileTiny remain not compacted and causing OOM.

What is changed and how it works?

Move the in-memory version list compaction to a background pool that is inited when PS v2 instances are created.

Check List

Tests

• Unit test
• Integration test
• Manual test (add detailed scripts or steps below)
  
• 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

Fix an issue that causes OOM with high throughput write

[ti-chi-bot]

[REVIEW NOTIFICATION]

This pull request has not been approved.

To complete the pull request process, please ask the reviewers in the list to review by filling /cc @reviewer in the comment.
After your PR has acquired the required number of LGTMs, you can assign this pull request to the committer in the list by filling /assign @committer in the comment to help you merge this pull request.

The full list of commands accepted by this bot can be found here.

Reviewer can indicate their review by submitting an approval review.
Reviewer can cancel approval by submitting a request changes review.

[ti-chi-bot]

@ti-chi-bot: This cherry pick PR is for a release branch and has not yet been approved by release team.
Adding the do-not-merge/cherry-pick-not-approved label.

To merge this cherry pick, it must first be approved by the collaborators.

AFTER it has been approved by collaborators, please ping the release team in a comment to request a cherry pick review.

Instructions for interacting with me using PR comments are available here. If you have questions or suggestions related to my behavior, please file an issue against the kubernetes/test-infra repository.

[JaySon-Huang]

It is recommended to upgrade to 5.4.4/6.1.4 or later