planner: fix the issue that UnionAll didn't handle the range bump case (#52542)

[ti-chi-bot]

This is an automated cherry-pick of #52542

What problem does this PR solve?

Issue Number: close #52472

Problem Summary:

The UnionAll should use types.AggFieldType to aggregate the fieldTypes. This function will handle the bump of range. For example, the aggregate of signed and unsigned long will give signed long long.

What changed and how does it work?

Use types.AggFieldType instead of types.MergeFieldType.

This PR also makes types.MergeFieldType private, as it's easy to make such mistakes.

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

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

Fix the issue that the content of the result of `union all` may overflow the type.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Please upload report for BASE (release-7.5@33cae3a). Learn more about missing BASE report.

Additional details and impacted files

@@               Coverage Diff                @@
##             release-7.5     #53211   +/-   ##
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  Coverage               ?   72.3265%           
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  Files                  ?       1411           
  Lines                  ?     412594           
  Branches               ?          0           
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  Hits                   ?     298415           
  Misses                 ?      94264           
  Partials               ?      19915           

Flag	Coverage Δ
unit	72.3265% <100.0000%> (?)

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

Components	Coverage Δ
dumpling	53.9913% <0.0000%> (?)
parser	∅ <0.0000%> (?)
br	53.4358% <0.0000%> (?)

[YangKeao]

LGTM

[ti-chi-bot]

[APPROVALNOTIFIER] This PR is APPROVED

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

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• OWNERS [YangKeao,hawkingrei]

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[ti-chi-bot]

[LGTM Timeline notifier]

Timeline:

• 2024-05-23 05:45:30.466485391 +0000 UTC m=+2323284.223620963: ☑️ agreed by hawkingrei.
• 2024-05-23 06:06:10.713838684 +0000 UTC m=+2324524.470974255: ☑️ agreed by YangKeao.