Avoid fetching of statistics from DeterminePartitionCount in small cluster

[raunaqmorarka]

Description

When the max possible tasks count is close to the min partition count, it is not worth paying the cost of fetching statistics to determine optimal partitions count

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## General
* Improve performance of simple queries in clusters with small number of nodes. ({issue}`26525`)

[Copilot]

Pull Request Overview

This PR optimizes performance for simple queries in small clusters by avoiding unnecessary statistics fetching when determining partition counts. The optimization triggers when the maximum possible task count is close to the minimum partition count, eliminating the overhead of statistics collection in scenarios where it provides minimal benefit.

• Early exit from partition count determination when maxPossiblePartitionCount <= 2 * minPartitionCount
• Reuse of the calculated maxPossiblePartitionCount value to avoid redundant computations
• Updated test cases to verify the new behavior and adjust edge case scenarios

Reviewed Changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated no comments.

File	Description
DeterminePartitionCount.java	Adds early exit logic and reuses task count estimation to avoid statistics fetching in small clusters
TestDeterminePartitionCount.java	Adds new test case and updates existing tests to verify the optimization behavior

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[raunaqmorarka]

/test-with-secrets sha=7ec454205c90180e60e225bcfc929e0f847da5c5

[github-actions]

The CI workflow run with tests that require additional secrets has been started: https://github.com/trinodb/trino/actions/runs/17393527142