Avoid out of bound InsertRangeFrom exception in MergingSortedBlockInputStream (#8445)

[ti-chi-bot]

This is an automated cherry-pick of #8445

What problem does this PR solve?

Issue Number: close #8438

Problem Summary:

What is changed and how it works?

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

None

[yibin87]

/cherry-pick-invite

[ti-chi-bot]

@yibin87 you're already a collaborator in repo ti-chi-bot/tiflash

[yibin87]

LGTM

[ti-chi-bot]

@yibin87: adding LGTM is restricted to approvers and reviewers in OWNERS files.

In response to this:

LGTM

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[xzhangxian1008]

LGTM

[ti-chi-bot]

@xzhangxian1008: adding LGTM is restricted to approvers and reviewers in OWNERS files.

In response to this:

LGTM

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.

[ti-chi-bot]

[APPROVALNOTIFIER] This PR is NOT APPROVED

This pull-request has been approved by: xzhangxian1008, yibin87

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