Remove legacy compatibility code for PHP versions < 8.1

[ihor-sviziev]

Description (*)

This pull request removes code that was designed to be ran on PHP <8.1.
Also, removed checks for PHP_VERSION_ID contact availability, since it's available in all PHP versions

Related Pull Requests

Fixed Issues (if relevant)

1. Fixes magento/magento2#<issue_number>

Manual testing scenarios (*)

1. ...
2. ...

Questions or comments

Contribution checklist (*)

• Pull request has a meaningful description of its purpose
• All commits are accompanied by meaningful commit messages
• All new or changed code is covered with unit/integration tests (if applicable)
• README.md files for modified modules are updated and included in the pull request if any README.md predefined sections require an update
• All automated tests passed successfully (all builds are green)

Resolved issues:

1. resolves [Issue] Remove legacy compatibility code for PHP versions < 8.1 #39891: Remove legacy compatibility code for PHP versions < 8.1

[m2-assistant]

Hi @ihor-sviziev. Thank you for your contribution!
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[Copilot]

Copilot wasn't able to review any files in this pull request.

Files not reviewed (5)

• app/bootstrap.php: Language not supported
• dev/tests/static/framework/bootstrap.php: Language not supported
• dev/tests/unit/framework/bootstrap.php: Language not supported
• lib/internal/Magento/Framework/DB/DataConverter/SerializedToJson.php: Language not supported
• lib/internal/Magento/Framework/DB/Test/Unit/DB/Statement/MysqlTest.php: Language not supported

[ihor-sviziev]

@magento run all tests

[ihor-sviziev]

@magento run all tests

[engcom-Hotel]

@magento create issue