[foreign-memaccess+abi] RFR: Convert classes into records

[Jorn Vernee]

On Thu, 22 Sep 2022 07:18:10 GMT, Per Minborg <duke at openjdk.org> wrote:

> This PR converts some of the regular classes into records.

LGTM

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Marked as reviewed by jvernee (Committer).

PR: https://git.openjdk.org/panama-foreign/pull/731