Utilize the reusable PHPUnit workflow for code coverage reporting.

[desrosj]

The workflow responsible for generating code coverage reports and submitting them to Codecov.io (coverage analysis page) has a few shortcomings. Mainly, the logic for setting up and running PHPUnit tests is duplicated making more work for maintaining.

The workflow should be updated to make use of the reusable-phpunit-tests-v#.yml reusable workflow file.

Other improvements that can be made:

• There is currently no concurrency configured for this workflow. This prevents multiple workflows for the same change from being run at the same time. For PRs, only the newest one should run, and there should only ever be one running at a time for a specific commit.
• The workflow currently runs 4 different jobs to generate two report formats each for multisite and single site. PHPUnit supports generating multiple reports at the same time. The number of jobs can be cut in half.
• The workflow only runs for PRs when related files are changed. But when it runs, the report is not submitted to Codecov.io. This is supported and should be done as a way to fully test the workflow.

Trac ticket: https://core.trac.wordpress.org/ticket/62296

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This Pull Request is for code review only. Please keep all other discussion in the Trac ticket. Do not merge this Pull Request. See GitHub Pull Requests for Code Review in the Core Handbook for more details.

[github-actions]

Test using WordPress Playground

The changes in this pull request can previewed and tested using a WordPress Playground instance.

WordPress Playground is an experimental project that creates a full WordPress instance entirely within the browser.

Some things to be aware of

• The Plugin and Theme Directories cannot be accessed within Playground.
• All changes will be lost when closing a tab with a Playground instance.
• All changes will be lost when refreshing the page.
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For more details about these limitations and more, check out the Limitations page in the WordPress Playground documentation.

Test this pull request with WordPress Playground.

[github-actions]

The following accounts have interacted with this PR and/or linked issues. I will continue to update these lists as activity occurs. You can also manually ask me to refresh this list by adding the props-bot label.

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Props desrosj.

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[desrosj]

Merged in https://core.trac.wordpress.org/changeset/59287.