dxf: refactor failpoints in scheduler

[D3Hunter]

What problem does this PR solve?

Issue Number: ref #57497

Problem Summary:

What changed and how does it work?

• use failpoint.InjectCall to reduce code pollution
• abstract a getTaskClone method

Check List

Tests

• [x] Unit test
• [ ] Integration test
• [ ] Manual test (add detailed scripts or steps below)
• [ ] No need to test

  • [ ] I checked and no code files have been changed.

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

[tiprow[bot]]

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[codecov[bot]]

Codecov Report

Attention: Patch coverage is 96.42857% with 1 line in your changes missing coverage. Please review.

Project coverage is 73.4438%. Comparing base (d8c9190) to head (8690fea). Report is 10 commits behind head on master.

Additional details and impacted files

```diff @@ Coverage Diff @@ ## master #57566 +/- ## ================================================ + Coverage 72.8374% 73.4438% +0.6064% ================================================ Files 1676 1676 Lines 463557 467078 +3521 ================================================ + Hits 337643 343040 +5397 + Misses 105100 103202 -1898 - Partials 20814 20836 +22 ``` | [Flag](https://app.codecov.io/gh/pingcap/tidb/pull/57566/flags?src=pr&el=flags&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=pingcap) | Coverage Δ | | |---|---|---| | [integration](https://app.codecov.io/gh/pingcap/tidb/pull/57566/flags?src=pr&el=flag&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=pingcap) | `43.4339% <7.1428%> (?)` | | | [unit](https://app.codecov.io/gh/pingcap/tidb/pull/57566/flags?src=pr&el=flag&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=pingcap) | `72.2277% <96.4285%> (-0.0008%)` | :arrow_down: | Flags with carried forward coverage won't be shown. [Click here](https://docs.codecov.io/docs/carryforward-flags?utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=pingcap#carryforward-flags-in-the-pull-request-comment) to find out more. | [Components](https://app.codecov.io/gh/pingcap/tidb/pull/57566/components?src=pr&el=components&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=pingcap) | Coverage Δ | | |---|---|---| | [dumpling](https://app.codecov.io/gh/pingcap/tidb/pull/57566/components?src=pr&el=component&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=pingcap) | `52.7673% <ø> (+0.1129%)` | :arrow_up: | | [parser](https://app.codecov.io/gh/pingcap/tidb/pull/57566/components?src=pr&el=component&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=pingcap) | `∅ <ø> (∅)` | | | [br](https://app.codecov.io/gh/pingcap/tidb/pull/57566/components?src=pr&el=component&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=pingcap) | `45.4058% <ø> (+0.0491%)` | :arrow_up: |

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[ti-chi-bot[bot]]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: lance6716, wjhuang2016

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

The pull request process is described here

Needs approval from an approver in each of these files: - ~~[OWNERS](https://github.com/pingcap/tidb/blob/master/OWNERS)~~ [lance6716,wjhuang2016] - ~~[pkg/disttask/OWNERS](https://github.com/pingcap/tidb/blob/master/pkg/disttask/OWNERS)~~ [lance6716,wjhuang2016] 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[bot]]

[LGTM Timeline notifier]

Timeline:

• 2024-11-21 02:20:13.993752564 +0000 UTC m=+84601.613407080: :ballot_box_with_check: agreed by lance6716.
• 2024-11-21 02:59:25.048429979 +0000 UTC m=+86952.668084495: :ballot_box_with_check: agreed by wjhuang2016.

[D3Hunter]

/retest

[tiprow[bot]]

@D3Hunter: Cannot trigger testing until a trusted user reviews the PR and leaves an /ok-to-test message.

In response to [this](https://github.com/pingcap/tidb/pull/57566#issuecomment-2489981938): >/retest Instructions for interacting with me using PR comments are available [here](https://git.k8s.io/community/contributors/guide/pull-requests.md). If you have questions or suggestions related to my behavior, please file an issue against the [kubernetes-sigs/prow](https://github.com/kubernetes-sigs/prow/issues/new?title=Prow%20issue:) repository.