RFR: 8368178: Add specialization of SequencedCollection methods to emptyList, singletonList and nCopies [v2]

[Per Minborg]

On Sun, 21 Sep 2025 10:31:06 GMT, Tagir F. Valeev <tvaleev at openjdk.org> wrote:

>> Please review this small change. If you have more ideas which classes may miss specializations of SequencedCollection methods, I can add them to this PR as well.
>
> Tagir F. Valeev has updated the pull request incrementally with two additional commits since the last revision:
> 
>  - Remove extra asterisk to prevent jtreg comment from being parsed as javadoc
>  - JDK-8368178 Add specialization of SequencedCollection methods to emptyList, singletonList and nCopies

In theory, `EmptyList` and `SingletonList` could implement `SequencedCollection`. Same for map.

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PR Comment: https://git.openjdk.org/jdk/pull/27406#issuecomment-3317215935