TiFlash: add a section of data compaction

[shichun-0415]

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• v6.4 (TiDB 6.4 versions)
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What is the related PR or file link(s)?

• This PR is translated from: modify tune-tiflash-performance.md docs-cn#12513
• Other reference link(s):

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• Delete files
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[ti-chi-bot]

[REVIEW NOTIFICATION]

This pull request has been approved by:

• hfxsd

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[hfxsd]

Rest LGTM

[shichun-0415]

/status LGT2

[shichun-0415]

/merge

[ti-chi-bot]

This pull request has been accepted and is ready to merge.

Commit hash: 74fe616

[ti-chi-bot]

In response to a cherrypick label: new pull request created to branch release-6.5: #11939.