test: migrate math/base/special/floorn to ULP-based testing

[Planeshifter]

Resolves a part of #11352.

Description

What is the purpose of this pull request?

This pull request:

• migrates the test suite for math/base/special/floorn from relative tolerance testing (a computed EPS-based delta/tol comparison) to ULP difference testing using @stdlib/assert/is-almost-same-value, per the pattern described in [RFC]: Migrate math/base/special packages from relative tolerance testing to ULP difference testing (tracking issue) #11352.
• applies the same change to both test/test.js and test/test.native.js, which contained an identical tolerance block in the "supports rounding very small numbers (including subnormals)" test case.
• determines the minimum required ULP tolerance agentically: starting from a generous bound (64 ULPs) and lowering it until the full fixture set no longer passed, then confirming the tightest passing value is deterministic (no FMA/architecture flakiness) by re-running the suite. The minimum required ULP difference is 1.

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.

Verified locally:

• node_modules/.bin/tape test/test.js → 450/450 passing, run twice to confirm determinism at ULP=1.
• node_modules/.bin/eslint test/test.js test/test.native.js → clean.
• test/test.native.js test cases are skipped locally (no compiled native addon available in this environment), but the tolerance block was identical in source and was updated identically to test.js.
• Only the two test files changed; no package.json update was needed since @stdlib/assert/is-almost-same-value is an internal stdlib package.

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 (an AI coding assistant), converting the existing relative-tolerance test case to ULP-based assertions following the established pattern from previously merged conversions in this tracking issue (e.g. math/base/special/roundn, math/base/special/csc). The minimum ULP bound was determined empirically by running the actual test suite.

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@stdlib-js/reviewers

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Generated by Claude Code

[stdlib-bot]

Coverage Report

Package	Statements	Branches	Functions	Lines
math/base/special/floorn	$\\color{green}272/272$ $\\color{green}+100.00\\%$	$\\color{green}24/24$ $\\color{green}+100.00\\%$	$\\color{green}2/2$ $\\color{green}+100.00\\%$	$\\color{green}272/272$ $\\color{green}+100.00\\%$

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