RFR: 8336844: ZipConstants64 defines duplicate constants EXTID_ZIP64 and ZIP64_EXTID [v2]

[Liam Miller-Cushon]

> This change deduplicates constants in ZipConstants64 for the Zip64 Extended Information Extra Field Header ID (see APPNOTE.TXT 4.5.3).
> 
> I think there are arguments for consolidating on either `EXTID_ZIP64` or `ZIP64_EXTID`. The PR currently consolidates on `EXTID_ZIP64`, `ZIP64_EXTID` is also an option if there's a preference for that.
> 
> I noticed this while working on a zip64 bug in [JDK-8328995](https://bugs.openjdk.org/browse/JDK-8328995), I was reviewing places that handled zip64 extra fields and initially missed some because I was only looking at one of the constants.

Liam Miller-Cushon has updated the pull request with a new target base due to a merge or a rebase. The incremental webrev excludes the unrelated changes brought in by the merge/rebase. The pull request contains three additional commits since the last revision:

 - Merge remote-tracking branch 'origin/master' into zip64_extid
 - Update copyright year
 - 8336844: ZipConstants64 defines duplicate constants EXTID_ZIP64 and EXTID_ZIP64.

-------------

Changes:
  - all: https://git.openjdk.org/jdk/pull/20264/files
  - new: https://git.openjdk.org/jdk/pull/20264/files/3b975c24..48bb222e

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=20264&range=01
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=20264&range=00-01

  Stats: 889 lines in 46 files changed: 673 ins; 101 del; 115 mod
  Patch: https://git.openjdk.org/jdk/pull/20264.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/20264/head:pull/20264

PR: https://git.openjdk.org/jdk/pull/20264