[jdk11u-dev] RFR: 8187649: ArrayIndexOutOfBoundsException in java.util.JapaneseImperialCalendar

[Zhengyu Gu]

A clean backport for parity with Oracle 11.0.14.

Test:

- [x] jdk/java/util/Calendar/CalendarTestScripts/JapaneseTests.java  test passed

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Commit messages:
 - Backport bea4109ef75a6536af4296db56e6ec90ab0f30fc

Changes: https://git.openjdk.java.net/jdk11u-dev/pull/460/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jdk11u-dev&pr=460&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8187649
  Stats: 46 lines in 3 files changed: 36 ins; 0 del; 10 mod
  Patch: https://git.openjdk.java.net/jdk11u-dev/pull/460.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk11u-dev pull/460/head:pull/460

PR: https://git.openjdk.java.net/jdk11u-dev/pull/460