RFR: 8296246: Update Unicode Data Files to Version 15.1.0 [v4]

[Naoto Sato]

> This PR is to incorporate the latest Unicode 15.1, which was released yesterday. Besides the usual character data update, an upgraded implementation of RegEx which reflects the Indic Conjunct Break specified in the latest [Unicode Annex #29 ("Unicode Text Segmentation")](https://unicode.org/reports/tr29/) is included. A corresponding CSR has also been drafted.

Naoto Sato has updated the pull request incrementally with one additional commit since the last revision:

  Update make/jdk/src/classes/build/tools/generateextraproperties/GenerateExtraProperties.java
  
  Co-authored-by: Steven R. Loomis <srl295 at gmail.com>

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Changes:
  - all: https://git.openjdk.org/jdk/pull/15728/files
  - new: https://git.openjdk.org/jdk/pull/15728/files/31e397ce..415418f0

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=15728&range=03
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=15728&range=02-03

  Stats: 2 lines in 1 file changed: 0 ins; 0 del; 2 mod
  Patch: https://git.openjdk.org/jdk/pull/15728.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/15728/head:pull/15728

PR: https://git.openjdk.org/jdk/pull/15728