<i18n dev> RFR: 8295232: "java.locale.useOldISOCodes" property is read lazily

[Naoto Sato]

Fixed to utilize `StaticProperty` so that the system property value for `java.locale.useOldISOCodes` set on the command line is honored even with lazy `Locale` initialization.

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Commit messages:
 - 8295232: "java.locale.useOldISOCodes" property is read lazily

Changes: https://git.openjdk.org/jdk/pull/10683/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=10683&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8295232
  Stats: 71 lines in 3 files changed: 69 ins; 1 del; 1 mod
  Patch: https://git.openjdk.org/jdk/pull/10683.diff
  Fetch: git fetch https://git.openjdk.org/jdk pull/10683/head:pull/10683

PR: https://git.openjdk.org/jdk/pull/10683