test: migrate stats/base/dists/gumbel/entropy to ULP-based assertions

[kgryte]

Resolves a part of #11352.

Description

What is the purpose of this pull request?

This pull request:

• migrates the tests for stats/base/dists/gumbel/entropy from relative tolerance testing to ULP difference testing, per [RFC]: Migrate math/base/special packages from relative tolerance testing to ULP difference testing (tracking issue) #11352.
• replaces the delta/tol computation and t.ok( delta <= tol, ... ) assertion in the Julia fixture loops of test/test.js and test/test.native.js with t.strictEqual( isAlmostSameValue( y, expected[ i ], 1 ), true, 'returns expected value' );.
• adds the @stdlib/assert/is-almost-same-value require and drops the now unused @stdlib/math/base/special/abs and @stdlib/constants/float64/eps requires.

Final ULP constant: 1 (used in both test/test.js and test/test.native.js).

This is the measured minimum. Over the full 100-element Julia fixture set, the largest observed ULP difference between the returned and expected values is exactly 1; at 0 ULP, 16 of the 110 assertions fail. The suite was run twice at the final value with identical results (110/110 passing, no FMA/arch variation). Consistent with the convention in already-migrated sibling packages (e.g. lognormal/entropy, normal/entropy), the same bound is used in the native test file.

Only the two test files are changed.

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.

• make test TESTS_FILTER=".*/stats/base/dists/gumbel/entropy/.*" could not be used in this environment: make install-node-modules fails because es-object-atoms@^1.1.2 is not published (the registry has at most 1.1.1). This is a pre-existing dependency-resolution failure unrelated to this change. The package's test files were instead executed directly against the repository's lib/node_modules tree, giving 110/110 passing for test/test.js; test/test.native.js skips, as the native add-on is not built.
• Linting was run with the repository's own configuration (etc/eslint/.eslintrc.tests.js) over both changed files and is clean. The editorconfig-checker step could not execute because its binary is downloaded from GitHub releases, which is unavailable here; both files were verified manually against .editorconfig (LF line endings, UTF-8, tab indentation, no trailing whitespace, final newline).

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

If you answered "yes" to using AI assistance, please provide a short disclosure indicating how you used AI assistance. This helps reviewers determine how much scrutiny to apply when reviewing your contribution. Example disclosures: "This PR was written primarily by Claude Code." or "I consulted ChatGPT to understand the codebase, but the proposed changes were fully authored manually by myself.".

This PR was authored by Claude Code, running as an unattended scheduled task. Claude studied #11352 and the already-migrated sibling packages to mirror the established idiom, applied the migration, and determined the ULP bound empirically by measuring the per-fixture ULP difference and confirming the suite fails at 0 and passes deterministically at 1.

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@stdlib-js/reviewers

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Generated by Claude Code

[stdlib-bot]

Coverage Report

Package	Statements	Branches	Functions	Lines
stats/base/dists/gumbel/entropy	$\\color{green}177/177$ $\\color{green}+100.00\\%$	$\\color{green}9/9$ $\\color{green}+100.00\\%$	$\\color{green}2/2$ $\\color{green}+100.00\\%$	$\\color{green}177/177$ $\\color{green}+100.00\\%$

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