<i18n dev> RFR: 8358819: The first year is not displayed correctly in Japanese Calendar

[Naoto Sato]

This regression was introduced by the removal of the COMPAT locale provider, which partially broke support for the first year in the Japanese calendar. In the Japanese calendar system, the first year of an era should be formatted using the character "元" rather than the numeral "1". The issue arises from a difference in how pattern character lengths are interpreted between CLDR and SimpleDateFormat. The existing `JapaneseEraNameTest` has been updated to cover this fix.

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Commit messages:
 - initial commit

Changes: https://git.openjdk.org/jdk/pull/25732/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=25732&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8358819
  Stats: 197 lines in 3 files changed: 120 ins; 66 del; 11 mod
  Patch: https://git.openjdk.org/jdk/pull/25732.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/25732/head:pull/25732

PR: https://git.openjdk.org/jdk/pull/25732