[Issue] Remove legacy compatibility code for PHP versions < 8.1

[m2-assistant]

This issue is automatically created based on existing pull request: #39882: Remove legacy compatibility code for PHP versions < 8.1

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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)

[engcom-Dash]

@ihor-sviziev Thank you for the report & collaboration!

Looking at the PR changes we can confirm that for PHP version < 8.0.0 legacy code can be removed. PHP_VERSION_ID is available in all the PHP versions hence we can safely remove the checks for it. Also, T_NAME_QUALIFIED & T_NAME_FULLY_QUALIFIED are available in versions starting from 8.0.0.

Hence confirming the issue.