RFR: 8287860: Revise usage of volatile in j.u.Locale [v3]

[Сергей Цыпанов]

> - cached hash code of `Locale` and `Locale$LanguageRange` shouldn't be volatile, even in case of race in the worst case it is recalculated at most once per thread
> - `defaultLocale` field is read multiple times in `initDefault()`
> - `isoLanguages` is accessed multiple times in `getISOLanguages()`
> - `languageTag` is read twice in `toLanguageTag()`

Сергей Цыпанов has updated the pull request incrementally with one additional commit since the last revision:

  8287860: Rename local vars

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Changes:
  - all: https://git.openjdk.java.net/jdk/pull/9041/files
  - new: https://git.openjdk.java.net/jdk/pull/9041/files/d4534346..454621d4

Webrevs:
 - full: https://webrevs.openjdk.java.net/?repo=jdk&pr=9041&range=02
 - incr: https://webrevs.openjdk.java.net/?repo=jdk&pr=9041&range=01-02

  Stats: 14 lines in 1 file changed: 0 ins; 0 del; 14 mod
  Patch: https://git.openjdk.java.net/jdk/pull/9041.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/9041/head:pull/9041

PR: https://git.openjdk.java.net/jdk/pull/9041