<i18n dev> RFR: 8285844: TimeZone.getTimeZone(ZoneOffset) does not work for all ZoneOffsets and returns GMT unexpected

[Naoto Sato]

This is to extend the `Custom ID`s in `java.util.TimeZone` class to support second-level resolution, enabling round trips with `java.time.ZoneOffset`s. Corresponding CSR is also being drafted.

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Commit messages:
 - 8285844: TimeZone.getTimeZone(ZoneOffset) does not work for all ZoneOffsets and returns GMT unexpected

Changes: https://git.openjdk.java.net/jdk/pull/8606/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jdk&pr=8606&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8285844
  Stats: 145 lines in 4 files changed: 98 ins; 1 del; 46 mod
  Patch: https://git.openjdk.java.net/jdk/pull/8606.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/8606/head:pull/8606

PR: https://git.openjdk.java.net/jdk/pull/8606