RFR: 8303018: Unicode Emoji Properties [v3]

[Naoto Sato]

> Proposing accessor methods to Emoji properties defined in [Unicode Technical Standard #51](https://unicode.org/reports/tr51/) in `java.lang.Character` class. This is per a request from the client group, as well as refining the currently existing ad-hoc emoji implementation in regex. A CSR has also been drafted, and I would appreciate reviews for it too.

Naoto Sato has updated the pull request incrementally with two additional commits since the last revision:

 - InternalError message/mask constants cleanup
 - Indentation/print comment fix

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Changes:
  - all: https://git.openjdk.org/jdk/pull/13006/files
  - new: https://git.openjdk.org/jdk/pull/13006/files/0b7b7296..6b4eef94

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=13006&range=02
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=13006&range=01-02

  Stats: 66 lines in 2 files changed: 36 ins; 9 del; 21 mod
  Patch: https://git.openjdk.org/jdk/pull/13006.diff
  Fetch: git fetch https://git.openjdk.org/jdk pull/13006/head:pull/13006

PR: https://git.openjdk.org/jdk/pull/13006