Handle aliasing of collation names

[dbussink]

With MySQL 8.0.30 and later, utf8mb3 is always reported as the charset in output for SHOW CREATE TABLE which is what schemadiff uses. We already today normalize all charset output to use the utf8mb3 name to avoid any ambiguity in what is intended.

We didn't do this though for collations. Today if schemadiff is fed schemas generated both with MySQL 8.0.30 and older versions to compare, it would indicate there's a difference when there is none.

The change here always normalizes to use the more explicit utf8mb3_ names for the collation if it can be found, based on the charset aliases configured. This ensures that comparisons between such schemas don't see accidental or stray diffs that are not really changes.

Related Issue(s)

This is part of the #10203 schemadiff work.

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• "Backport me!" label has been added if this change should be backported
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[vitess-bot]

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[GuptaManan100]

Looks good to me!