test: migrate stats/incr/mrss 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/incr/mrss from relative tolerance testing to ULP difference testing, replacing the computed delta/tol comparison with isAlmostSameValue.
• uses a ULP bound of 0, which is the measured minimum: the accumulated moving residual sums of squares in the fixture set are exactly representable, so no non-zero ULP budget is required. Tightening from a higher starting bound, 0 is the smallest integer for which the full fixture set passes, and the suite was run twice at 0 to confirm determinism.
• removes the now unused @stdlib/constants/float64/eps and @stdlib/math/base/special/abs requires from the test file.

Only test/test.js is modified; the package has no test/test.native.js.

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.

• Final ULP constant: 0 (measured minimum; make test TESTS_FILTER=".*/stats/incr/mrss/.*" green on two consecutive runs, 98/98 assertions).
• make eslint-tests TESTS_FILTER=".*/stats/incr/mrss/.*" is clean.

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: it selected the package, mirrored the conversion idiom from already-migrated packages in the same family, and determined the minimum passing ULP bound by running the package test suite.

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https://claude.ai/code/session_01QmWdLdjeUxMBTmv5WheEGs

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Coverage Report

Package	Statements	Branches	Functions	Lines
stats/incr/mrss	$\\color{green}144/144$ $\\color{green}+100.00\\%$	$\\color{green}8/8$ $\\color{green}+100.00\\%$	$\\color{green}2/2$ $\\color{green}+100.00\\%$	$\\color{green}144/144$ $\\color{green}+100.00\\%$

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