ttl: always enable all read engines for TTL sessions (#56604)

[ti-chi-bot]

This is an automated cherry-pick of #56604

What problem does this PR solve?

Issue Number: close #56402

Problem Summary:

If a TiDB node doesn't enable TiKV read engine, running TTL task may fail if the table doesn't have tiflash replica.

What changed and how does it work?

This PR always enables all read engines for TTL sessions.

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

Fix the issue that if the `isolation-read.engines` config is set without `tikv`, the TTL task may fail.

[codecov]

Codecov Report

Attention: Patch coverage is 55.55556% with 12 lines in your changes missing coverage. Please review.

Please upload report for BASE (release-7.5@54efcc6). Learn more about missing BASE report.

Additional details and impacted files

@@               Coverage Diff                @@
##             release-7.5     #56805   +/-   ##
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  Coverage               ?   73.1330%           
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  Files                  ?       1415           
  Lines                  ?     420022           
  Branches               ?          0           
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  Hits                   ?     307175           
  Misses                 ?      93081           
  Partials               ?      19766           

Flag	Coverage Δ
unit	73.1330% <55.5555%> (?)

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

Components	Coverage Δ
dumpling	52.9400% <0.0000%> (?)
parser	∅ <0.0000%> (?)
br	54.5399% <0.0000%> (?)

[YangKeao]

LGTM

[ti-chi-bot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: lcwangchao, YangKeao

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• OWNERS [YangKeao,lcwangchao]

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[ti-chi-bot]

[LGTM Timeline notifier]

Timeline:

• 2024-10-30 02:19:25.017077158 +0000 UTC m=+402677.856232704: ☑️ agreed by lcwangchao.
• 2024-10-30 03:00:23.05412151 +0000 UTC m=+405135.893277054: ☑️ agreed by YangKeao.