Fix Android DateTimeFormat hour-cycle selection and midnight formatting

[mozzius]

Summary

Android Hermes reports the requested h11/h24 cycle but formats the midnight hour using h12/h23, and its hour12 choice can disagree with the locale preferred cycle. Use Android ICU to select the locale preferred 12- or 24-hour cycle, preserve the exact resolved hour symbol in the final pattern, and omit day-period fields for 24-hour styled skeletons. The pre-API-24 java.text backend retains its existing selection behavior.

This is the Android counterpart to #2208 and addresses #2209. Standalone React Native / Chromium WebView reproduction: https://github.com/mozzius/hermes-datetimeformat-repro

Test plan

• On an Android 15 emulator, run the focused Hermes Intl instrumentation regression. It checks h11/h12/h23/h24 at midnight, hour12 locale preference, option precedence, and the presence or absence of dayPeriod parts.
• In the linked reproducer, compare native Hermes to WebView at local midnight; h11 must display 0 and h24 must display 24.

The focused regression passes on API 35. The entire HermesIntlAndroidTest class currently has unrelated failures in this checkout: three unavailable asset files and two expected regular spaces where Android 15 ICU emits a narrow no-break space.