[Tests] Rename subtree benchmark identifiers

[mrz1836]

What Changed

• Renamed the subtree benchmark helpers to follow Go's benchmark naming convention without underscores.

Why It Was Necessary

• Existing benchmark names violated linting rules that enforce Go's benchmark naming regex, generating maintainability warnings.

Testing Performed

• golangci-lint run (fails: binary built with Go 1.23 while module targets Go 1.24.3 in this environment)
• go test ./...

Impact / Risk

• Low risk: benchmark names only, no functional logic touched.
• Restores compliance with naming lint checks for benchmark functions.

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https://chatgpt.com/codex/tasks/task_e_68e848597c10832193af9e76674a9d6d

[Copilot]

Pull Request Overview

This PR renames Go benchmark function identifiers to comply with Go's benchmark naming conventions by removing underscores from function names.

• Renamed three benchmark functions to follow Go naming standards
• Removed underscores from benchmark function names to satisfy linting requirements
• Ensures compliance with Go's benchmark naming regex patterns

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[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud