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

[Tagir F. Valeev]

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.

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Commit messages:
 - JDK-8368178 Add specialization of SequencedCollection methods to emptyList, singletonList and nCopies

Changes: https://git.openjdk.org/jdk/pull/27406/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=27406&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8368178
  Stats: 148 lines in 4 files changed: 148 ins; 0 del; 0 mod
  Patch: https://git.openjdk.org/jdk/pull/27406.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/27406/head:pull/27406

PR: https://git.openjdk.org/jdk/pull/27406