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

[ujjwalv01]

Resolves a part of #11352.

Description

What is the purpose of this pull request?

This pull request:

• Migrates the unit tests for math/base/special/spencef (test.js and test.native.js) from relative tolerance testing to ULP difference testing using @stdlib/number/float32/base/assert/is-almost-same-value.

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

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Implementation Note on float32 ULP Tolerances:
Since spencef operates in single-precision (float32), this PR replaces absf and EPS with @stdlib/number/float32/base/assert/is-almost-same-value to assert bit-level differences.
When evaluating the 4 test loops against their corresponding Python test fixtures, the minimum required float32 ULP tolerances were determined as follows per Instruction "4" of RFC #11352:

• Small: 2 ULPs
• Medium: 10 ULPs
• Large: 3 ULPs
• Huge: 11 ULPs

These exact minimal thresholds achieve a 100% pass rate (2,105 / 2,105 passing) across all test suites, establishing the exact strict mathematical bounds required for precision validation. Lowering any of these bounds by even 1 ULP immediately triggers failures on the Python fixtures.

Checklist

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• Read, understood, and followed the contributing guidelines.

AI Assistance

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@stdlib-js/reviewers

[stdlib-bot]

Coverage Report

Package	Statements	Branches	Functions	Lines
math/base/special/spencef	$\\color{green}344/344$ $\\color{green}+100.00\\%$	$\\color{green}31/31$ $\\color{green}+100.00\\%$	$\\color{green}4/4$ $\\color{green}+100.00\\%$	$\\color{green}344/344$ $\\color{green}+100.00\\%$

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

[kgryte]

LGTM