RFR: 8317979: Use TZ database style abbreviations in the CLDR locale provider [v3]

[Naoto Sato]

> CLDR provides very few short names for time zones, such as PST/PDT. This will typically end up substituting names from the COMPAT provider. Once the COMPAT is removed, they will be displayed in the GMT format, i.e., GMT+XX:YY. Although some of the short names in the COMPAT provider are somewhat questionable (less common ones are simply made up from the long names by taking the initials), it would not be desirable for them to fall back to the GMT format.
> To mitigate the situation, CLDR can use the abbreviated names from the TZ database, which contains legacy (major) short names as FORMAT. The CLDR provider can use them instead of the GMT offset style. This enhancement is a precursor to the future removal of the COMPAT provider.

Naoto Sato has updated the pull request incrementally with one additional commit since the last revision:

  Delay populating GMT format at runtime. Reflecting review comments.

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Changes:
  - all: https://git.openjdk.org/jdk/pull/16206/files
  - new: https://git.openjdk.org/jdk/pull/16206/files/3d221558..4559203d

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=16206&range=02
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=16206&range=01-02

  Stats: 10 lines in 1 file changed: 4 ins; 1 del; 5 mod
  Patch: https://git.openjdk.org/jdk/pull/16206.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/16206/head:pull/16206

PR: https://git.openjdk.org/jdk/pull/16206