lightning: refactor to better reuse in load data

[D3Hunter]

What problem does this PR solve?

Issue Number: ref #40499

Problem Summary:

What is changed and how it works?

• move some code which can be reused to other package to avoid import cycle
• eliminate some func param which can be saved in the object

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

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

None

[ti-chi-bot]

[REVIEW NOTIFICATION]

This pull request has been approved by:

• lance6716
• okJiang

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[D3Hunter]

/merge

[ti-chi-bot]

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

Commit hash: 356f873

[D3Hunter]

/run-integration-br-test

[hawkingrei]

/retest

[D3Hunter]

https://ci.pingcap.net/blue/organizations/jenkins/tidb_ghpr_integration_br_test/detail/tidb_ghpr_integration_br_test/12291/pipeline pass

[D3Hunter]

/merge

[ti-chi-bot]

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

Commit hash: b0f4ce9