RFR: 8301492: Modernize equals() method of ResourceBundle.CacheKey and Bundles.CacheKey [v3]

[Sergey Tsypanov]

> `ResourceBundle.CacheKey.equals()` and `Bundles.CacheKey.equals()` are quire outdated. This simple clean-up modernizes them.

Sergey Tsypanov has updated the pull request incrementally with one additional commit since the last revision:

  Restore logic

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Changes:
  - all: https://git.openjdk.org/jdk/pull/12328/files
  - new: https://git.openjdk.org/jdk/pull/12328/files/82b03202..2b07e47e

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=12328&range=02
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=12328&range=01-02

  Stats: 4 lines in 1 file changed: 0 ins; 2 del; 2 mod
  Patch: https://git.openjdk.org/jdk/pull/12328.diff
  Fetch: git fetch https://git.openjdk.org/jdk pull/12328/head:pull/12328

PR: https://git.openjdk.org/jdk/pull/12328