RFR: 7903270: Util classes should be final and have a private constructor [v7]

[Athijegannathan Sundararajan]

On Tue, 20 Sep 2022 09:35:48 GMT, Per Minborg <duke at openjdk.org> wrote:

>> This PR makes some of the classes and fields `final`. Also, a general cleanup of the `RuntimeHelper` class is proposed.
>> 
>> There are some files that are "overhidden" (by attempting to "override"/hide static methods). This will be fixed in a separate PR and so these classes are not affected in this PR.
>
> Per Minborg has updated the pull request incrementally with one additional commit since the last revision:
> 
>   Update class

LGTM

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Marked as reviewed by sundar (Committer).

PR: https://git.openjdk.org/jextract/pull/65