Storages: Fix read ranges of FastScan

[JinheLin]

What problem does this PR solve?

Issue Number: close #9118

What is changed and how it works?

Shrinking the read ranges of FastScan.

Check List

Tests

• [x] 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 the read ranges of FastScan to reduce duplicate data

[ti-chi-bot[bot]]

[LGTM Timeline notifier]

Timeline:

• 2024-06-05 06:52:06.00215821 +0000 UTC m=+3450479.759293793: :ballot_box_with_check: agreed by CalvinNeo.
• 2024-06-05 07:14:20.660879789 +0000 UTC m=+3451814.418015364: :ballot_box_with_check: agreed by Lloyd-Pottiger.

[Lloyd-Pottiger]

/hold

[JinheLin]

/unhold

[ti-chi-bot[bot]]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: CalvinNeo, JaySon-Huang, Lloyd-Pottiger

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

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Needs approval from an approver in each of these files: - ~~[OWNERS](https://github.com/pingcap/tiflash/blob/master/OWNERS)~~ [CalvinNeo,JaySon-Huang,Lloyd-Pottiger] Approvers can indicate their approval by writing `/approve` in a comment Approvers can cancel approval by writing `/approve cancel` in a comment

[ti-chi-bot]

In response to a cherrypick label: new pull request created to branch release-7.5: #9121.

[ti-chi-bot]

In response to a cherrypick label: new pull request created to branch release-8.1: #9122.

[ti-chi-bot]

In response to a cherrypick label: new pull request created to branch release-7.1: #9123.