<i18n dev> RFR: 8316150: Refactor get chars and string size

Wed Sep 13 01:45:13 UTC 2023

1. Reduce duplicate stringSize code
2. Move java.lang.StringLatin1.getChars to jdk.internal.util.DecimalDigits::getCharLatin1，not only java.lang, other packages also need to use this method

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Commit messages:
 - move StringLatin1::getChars to jdk.internal.util.DecimalDigits::getCharsLatin1
 - move *::stringSize to jdk.internal.util.DecimalDigits::stringSize

Changes: https://git.openjdk.org/jdk/pull/15699/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=15699&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8316150
  Stats: 374 lines in 9 files changed: 153 ins; 190 del; 31 mod
  Patch: https://git.openjdk.org/jdk/pull/15699.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/15699/head:pull/15699

PR: https://git.openjdk.org/jdk/pull/15699