[LANG-1823] LocaleUtils.toLocale cannot parse valid JDK Locale string containing '#'

[garydgregory]

[LANG-1823] LocaleUtils.toLocale cannot parse valid JDK Locale string
containing '#' (e.g., from Locale.getAvailableLocales())

• [LANG-879]
  LocaleUtils test fails with new Locale "ja_JP_JP_#u-ca-japanese" of JDK7
• See https://docs.oracle.com/en/java/javase/25/docs/api/java.base/java/util/Locale.html#special_cases_constructor

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