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

[Planeshifter]

Resolves a part of #11352.

Description

What is the purpose of this pull request?

This pull request:

• migrates test/test.js and test/test.native.js in math/base/special/acscdf from relative-tolerance (EPS-scaled delta/tol) assertions to ULP-difference assertions via @stdlib/number/float32/base/assert/is-almost-same-value (the single-precision variant, following the precedent of asecdf, as acscdf is a single-precision function).
• uses the minimum required ULP value (2) for both the negative and positive fixture test blocks. This was determined empirically: ULP = 1 fails (142 of 6009 assertions), ULP = 2 passes all 6009 assertions, confirmed deterministic across multiple consecutive runs. A direct computation of the ULP distance between actual and expected values over both fixture sets confirms a max distance of 2 ULPs in each case.
• removes the now-unused abs require and delta/tol variables, and collapses the obsolete exact-equality short-circuit branches. The EPS require is retained, as it is still used by the uniform() domain-guard NaN tests.

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.

The native add-on could not be built in this sandboxed environment (no node-gyp/toolchain available), so test/test.native.js could not be executed directly; however, it mirrors the same ULP value (2) as the JS test, consistent with prior conversions in this series (e.g. cscd, #13664) that noted the same limitation.

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 by Claude Code (test migration and minimum-ULP determination via direct computation of ULP distance over the fixture sets).

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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/acscdf	$\\color{green}197/197$ $\\color{green}+100.00\\%$	$\\color{green}5/5$ $\\color{green}+100.00\\%$	$\\color{green}2/2$ $\\color{green}+100.00\\%$	$\\color{green}197/197$ $\\color{green}+100.00\\%$

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