RFR: 8367382: Expand use of representation equivalence terminology

[Joe Darcy]

Small doc enhancement to use the term "representation equivalence" in a few more locations.

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Commit messages:
 - JDK-8367382: Expand use of representation equivalence terminology

Changes: https://git.openjdk.org/jdk/pull/27232/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=27232&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8367382
  Stats: 26 lines in 3 files changed: 24 ins; 0 del; 2 mod
  Patch: https://git.openjdk.org/jdk/pull/27232.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/27232/head:pull/27232

PR: https://git.openjdk.org/jdk/pull/27232