[lworld] RFR: JDK-8269172: Add java.util.Objects.newIdentity method

[Roger Riggs]

Replaces the existing Objects.newIdentity() method with the matching method in JDK17.

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Commit messages:
 - JDK-8269172: Add java.util.Objects.newIdentity method

Changes: https://git.openjdk.java.net/valhalla/pull/459/files
 Webrev: https://webrevs.openjdk.java.net/?repo=valhalla&pr=459&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8269172
  Stats: 42 lines in 2 files changed: 27 ins; 14 del; 1 mod
  Patch: https://git.openjdk.java.net/valhalla/pull/459.diff
  Fetch: git fetch https://git.openjdk.java.net/valhalla pull/459/head:pull/459

PR: https://git.openjdk.java.net/valhalla/pull/459