MDEV-23962 Remove arc directory obsolete code and move it to mysql_upgrade

[hp77-creator]

• The Jira issue number for this PR is: MDEV-23962

Description

In the Jira ticket, requirement was to move the arc directory cleanup function to mysql_upgrade. I have done that and also added some tests to verify if the cleanup is happening properly and also added a test to see if we are not removing any unnecessary files

Release Notes

mysql_upgrade now also cleans up the obsolete arc directory and .frm file in it

How can this PR be tested?

This can be tested by running the following command:

mtr mysql_upgrade_arc_files_verify mysql_upgrade_arc_files_cleanup

If the changes are not amenable to automated testing, please explain why not and carefully describe how to test manually.

Basing the PR against the correct MariaDB version

• This is a new feature or a refactoring, and the PR is based against the main branch.
• This is a bug fix, and the PR is based against the earliest maintained branch in which the bug can be reproduced.

PR quality check

• I checked the CODING_STANDARDS.md file and my PR conforms to this where appropriate.
• For any trivial modifications to the PR, I am ok with the reviewer making the changes themselves.

[CLAassistant]

All committers have signed the CLA.

[hp77-creator]

@cvicentiu @grooverdan @vuvova Please let me know if this is fine. I have updated the existing tests as well.