RFR: 8282319: java.util.Locale method to stream available Locales [v4]

[Justin Lu]

> This PR adds a new method to java.util.Locale which returns Stream<Locale>
> 
> The contents of the Stream are composed of the same underlying elements as Locale.getAvailableLocales().
> 
> This method allows streaming of the Locale array without creating a defensive copy.

Justin Lu has updated the pull request incrementally with one additional commit since the last revision:

  Switch {@return for @return for consistency

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Changes:
  - all: https://git.openjdk.org/jdk/pull/12269/files
  - new: https://git.openjdk.org/jdk/pull/12269/files/b4d0ceff..3995a038

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=12269&range=03
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=12269&range=02-03

  Stats: 7 lines in 2 files changed: 3 ins; 2 del; 2 mod
  Patch: https://git.openjdk.org/jdk/pull/12269.diff
  Fetch: git fetch https://git.openjdk.org/jdk pull/12269/head:pull/12269

PR: https://git.openjdk.org/jdk/pull/12269