RFR: 8335637: Add explicit well-behaved expectations to Object.{toString, hashCode} [v3]

[Joe Darcy]

> Make well-behaved implementation expectations of Object.{toString, hashCode} explicit.

Joe Darcy has updated the pull request incrementally with one additional commit since the last revision:

  Respond to review feedback.

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Changes:
  - all: https://git.openjdk.org/jdk/pull/20063/files
  - new: https://git.openjdk.org/jdk/pull/20063/files/1182f5d7..66679fb8

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=20063&range=02
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=20063&range=01-02

  Stats: 3 lines in 1 file changed: 3 ins; 0 del; 0 mod
  Patch: https://git.openjdk.org/jdk/pull/20063.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/20063/head:pull/20063

PR: https://git.openjdk.org/jdk/pull/20063