disable two-level hash table for fine-grained agg if spill is not needed

[windtalker]

What problem does this PR solve?

Issue Number: close #10481

Problem Summary:
disable two-level hash table for fine-grained agg if spill is not needed.
In fact, for fine grained hash agg, we should also use a new spill algorithm for fine grained agg(we can actually spill data by threads instead of convert the hash table into two-level hash table), but this pr just keep the original behavior if spill is enabled.

What is changed and how it works?

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

None

[ti-chi-bot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: gengliqi

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[ti-chi-bot]

[LGTM Timeline notifier]

Timeline:

• 2025-10-16 07:31:58.107008103 +0000 UTC m=+338624.184260664: ☑️ agreed by gengliqi.

[ti-chi-bot]

@windtalker: The following tests failed, say /retest to rerun all failed tests or /retest-required to rerun all mandatory failed tests:

Test name	Commit	Details	Required	Rerun command
pull-unit-test	54667d6	link	true	/test pull-unit-test
pull-unit-next-gen	54667d6	link	true	/test pull-unit-next-gen

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