test: remove duplicate NaN test cases in normal mean

[SuYaSh-PaThAk04]

Resolves #9567 .

Description

What is the purpose of this pull request?

This pull request: removes exact duplicate test cases in the normal distribution mean tests (test.js and test.native.js) which did not provide additional coverage.
The duplicated assertions used identical inputs and expectations for a pure function, making them redundant. Removing them simplifies the test suite while preserving full coverage.

Related Issues

Does this pull request have any related issues?

This pull request has the following related issues:

• Closes [RFC] Duplicate test cases in normal mean package #9567

Questions

Any questions for reviewers of this pull request?

No.

Other

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No.

Checklist

Please ensure the following tasks are completed before submitting this pull request.

• Read, understood, and followed the contributing guidelines.

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@stdlib-js/reviewers

[stdlib-bot]

Coverage Report

Package	Statements	Branches	Functions	Lines
stats/base/dists/cosine/mean	$\color{green}175/175$ $\color{green}+100.00%$	$\color{green}9/9$ $\color{green}+100.00%$	$\color{green}2/2$ $\color{green}+100.00%$	$\color{green}175/175$ $\color{green}+100.00%$
stats/base/dists/gumbel/mean	$\color{green}176/176$ $\color{green}+0.00%$	$\color{green}9/9$ $\color{green}+0.00%$	$\color{green}2/2$ $\color{green}+0.00%$	$\color{green}176/176$ $\color{green}+0.00%$
stats/base/dists/laplace/mean	$\color{green}175/175$ $\color{green}+0.00%$	$\color{green}9/9$ $\color{green}+0.00%$	$\color{green}2/2$ $\color{green}+0.00%$	$\color{green}175/175$ $\color{green}+0.00%$
stats/base/dists/levy/mean	$\color{green}176/176$ $\color{green}+0.00%$	$\color{green}9/9$ $\color{green}+0.00%$	$\color{green}2/2$ $\color{green}+0.00%$	$\color{green}176/176$ $\color{green}+0.00%$
stats/base/dists/logistic/mean	$\color{green}175/175$ $\color{green}+0.00%$	$\color{green}9/9$ $\color{green}+0.00%$	$\color{green}2/2$ $\color{green}+0.00%$	$\color{green}175/175$ $\color{green}+0.00%$
stats/base/dists/lognormal/mean	$\color{green}176/176$ $\color{green}+0.00%$	$\color{green}9/9$ $\color{green}+0.00%$	$\color{green}2/2$ $\color{green}+0.00%$	$\color{green}176/176$ $\color{green}+0.00%$
stats/base/dists/normal/mean	$\color{green}175/175$ $\color{green}+0.00%$	$\color{green}9/9$ $\color{green}+0.00%$	$\color{green}2/2$ $\color{green}+0.00%$	$\color{green}175/175$ $\color{green}+0.00%$

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

[stdlib-bot]

PR Commit Message

test: remove duplicate NaN test cases in normal mean

PR-URL: https://github.com/stdlib-js/stdlib/pull/9588
Closes: https://github.com/stdlib-js/stdlib/issues/9567

Reviewed-by: Philipp Burckhardt <[email protected]>
Signed-off-by: Suyash Pathak <[email protected]>

Please review the above commit message and make any necessary adjustments.

[SuYaSh-PaThAk04]

Thank you @Planeshifter. Looking forward to more contributions!