ICU-22967 Remove explicit manipultaion of old-xmls.tar.bz2 in workflows

[mihnita]

The workflow was trying to repair old-xmls.tar.bz2

Which was broken (the first commit in my pull request #3375)
Although the right fix would have been to restore the file for good.
But this "fix" does not work now, on a removed file :-) (the second commit in the mentioned PR)
Anyway... the whole folder 'tools/multi' is not needed, so it should be good now.

Checklist

• Required: Issue filed: ICU-22967
• Required: The PR title must be prefixed with a JIRA Issue number. Example: "ICU-1234 Fix xyz"
• Required: Each commit message must be prefixed with a JIRA Issue number. Example: "ICU-1234 Fix xyz"
• Issue accepted (done by Technical Committee after discussion)
• Tests included, if applicable
• API docs and/or User Guide docs changed or added, if applicable

[roubert]

These changes look perfectly reasonable to me and I trust that you've verified that they work.

[mihnita]

Thank you!