test: migrate stats/base/snanstdevch to ULP-based assertions

[Planeshifter]

Resolves #{{TODO: add issue number}}.

Description

What is the purpose of this pull request?

This pull request:

• migrates the tests for stats/base/snanstdevch (test.ndarray.js, test.ndarray.native.js, test.snanstdevch.js, test.snanstdevch.native.js) from EPS-based tolerance checks to ULP-based assertions using @stdlib/number/float32/base/assert/is-almost-same-value.
• defines a single named constant ULP = 1 in each test file. This is the measured minimum: ULP = 0 fails 2 assertions per file in both the JS and native tests, and ULP = 1 passes all 36 assertions per file. The result was identical across two runs.

Related Issues

Does this pull request have any related issues?

This pull request has the following related issues:

• [RFC]: Migrate math/base/special packages from relative tolerance testing to ULP difference testing (tracking issue) #11352

Questions

Any questions for reviewers of this pull request?

No.

Other

Any other information relevant to this pull request? This may include screenshots, references, and/or implementation notes.

Only test files are changed. The idiom mirrors the earlier stats/base/snanstdevyc migration, except that the ULP value is a named constant instead of an inline literal.

Checklist

Please ensure the following tasks are completed before submitting this pull request.

• Read, understood, and followed the contributing guidelines.

AI Assistance

When authoring the changes proposed in this PR, did you use any kind of AI assistance?

• Yes
• No

If you answered "yes" above, how did you use AI assistance?

• Code generation (e.g., when writing an implementation or fixing a bug)
• Test/benchmark generation
• Documentation (including examples)
• Research and understanding

Disclosure

This PR was written primarily by Claude Code as an unattended scheduled task. The ULP bound was found by running the tests at decreasing values.

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@stdlib-js/reviewers

🤖 Generated with Claude Code

https://claude.ai/code/session_01AtqS3EoAjWia2i1d1JYGDD

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Generated by Claude Code

[stdlib-bot]

Coverage Report

Package	Statements	Branches	Functions	Lines
stats/base/snanstdevch	$\\color{green}365/365$ $\\color{green}+100.00\\%$	$\\color{green}14/14$ $\\color{green}+100.00\\%$	$\\color{green}4/4$ $\\color{green}+100.00\\%$	$\\color{green}365/365$ $\\color{green}+100.00\\%$

The above coverage report was generated for the changes in this PR.

[kgryte]

ULP values need to be inlined.

[stdlib-bot]

Thank you for working on this pull request. However, we cannot accept your contribution as the issue this pull request seeks to resolve has already been addressed in a different pull request or commit.

Thank you again for your interest in stdlib, and we look forward to reviewing your future contributions.