Simplify the system TimeZone retrieval. The new code behaves just as before in the most common case where `GetDynamicTimeZoneInformation` returns a known `TimeZoneKeyName`, and reduces the amount of second-guessing when the time zone is not known.
Method `getGMTOffsetID` was not modified. It is only used as a fallback when `findJavaTZ_md` fails, and while it doesn't look great, it's probably better than most of the alternatives. I verified that: - the `TimeZoneKeyName` contains non-localized values and is usable on both English and non-English systems, - tier1 and tier2 tests continue to pass - java/time tests continue to pass when the fallback paths are taken (`findJavaTZ_md` returns a `customZoneName` or a `NULL`) --------- - [x] I confirm that I make this contribution in accordance with the [OpenJDK Interim AI Policy](https://openjdk.org/legal/ai). ------------- Commit messages: - Clean up TimeZone_md Changes: https://git.openjdk.org/jdk/pull/33052/files Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=33052&range=00 Issue: https://bugs.openjdk.org/browse/JDK-8392957 Stats: 332 lines in 1 file changed: 17 ins; 305 del; 10 mod Patch: https://git.openjdk.org/jdk/pull/33052.diff Fetch: git fetch https://git.openjdk.org/jdk.git pull/33052/head:pull/33052 PR: https://git.openjdk.org/jdk/pull/33052
