<i18n dev> RFR: 8342863: Use pattern matching for instanceof in equals methods of wrapper classes

[Joe Darcy]

Noticed this refactoring opportunity while doing some other work in the area.

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Commit messages:
 - JDK-8342863: Use pattern matching for instanceof in equals methods of wrapper classes

Changes: https://git.openjdk.org/jdk/pull/21652/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=21652&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8342863
  Stats: 17 lines in 8 files changed: 0 ins; 1 del; 16 mod
  Patch: https://git.openjdk.org/jdk/pull/21652.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/21652/head:pull/21652

PR: https://git.openjdk.org/jdk/pull/21652