test: fix some tests for next-gen

[ekexium]

What problem does this PR solve?

Issue Number: close #63343

Problem Summary:
Fix failing tests in next-gen mode by adding appropriate kernel type checks and skipping incompatible tests.

What changed and how does it work?

1. readcommitted_test.go: Added next-gen kernel checks to skip TestFailedDMLConsistency1 and TestFailedDMLConsistency2 because next-gen hangs when acquiring pessimistic locks after failed DML with fair locking disabled
2. data_feature_usage_test.go:
   • Added kernel type check in TestTxnUsageInfo to only test fair locking settings in classic mode
   • Added skip for TestFairLockingUsage in next-gen mode since fair locking is not yet supported

These changes prevent test failures and hangs in next-gen environment while maintaining full test coverage in classic mode.

Check List

Tests

• 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

None

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 73.2120%. Comparing base (3d9a0eb) to head (0793616).
⚠️ Report is 6 commits behind head on master.

Additional details and impacted files

@@               Coverage Diff                @@
##             master     #63342        +/-   ##
================================================
+ Coverage   72.7832%   73.2120%   +0.4287%     
================================================
  Files          1832       1832                
  Lines        495794     496096       +302     
================================================
+ Hits         360855     363202      +2347     
+ Misses       113010     110997      -2013     
+ Partials      21929      21897        -32     

Flag	Coverage Δ
integration	42.0368% <ø> (?)
unit	72.2581% <ø> (+0.0061%)	⬆️

Flags with carried forward coverage won't be shown. Click here to find out more.

Components	Coverage Δ
dumpling	52.8700% <ø> (ø)
parser	∅ <ø> (∅)
br	46.5294% <ø> (-0.0026%)	⬇️

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[ti-chi-bot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: hawkingrei, zyguan

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• OWNERS [hawkingrei,zyguan]

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[ti-chi-bot]

[LGTM Timeline notifier]

Timeline:

• 2025-09-03 01:44:17.604837937 +0000 UTC m=+922949.482668891: ☑️ agreed by zyguan.
• 2025-09-03 03:20:05.418619703 +0000 UTC m=+928697.296450647: ☑️ agreed by hawkingrei.