<i18n dev> RFR: 8319640: ClassicFormat::parseObject (from DateTimeFormatter) does not conform to the javadoc and may leak DateTimeException

[Naoto Sato]

Fixing the `Format::parseObject(String, ParsePosition)` implementation in `DateTimeFormatter` class, to not throw `DateTimeException` but to return null.

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Commit messages:
 - initial commit

Changes: https://git.openjdk.org/jdk/pull/16586/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=16586&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8319640
  Stats: 39 lines in 2 files changed: 24 ins; 8 del; 7 mod
  Patch: https://git.openjdk.org/jdk/pull/16586.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/16586/head:pull/16586

PR: https://git.openjdk.org/jdk/pull/16586