Remove NativePluralRules since we are using ICU4J directly.

The following benchmark shows the time taken for ICU4C to
run quantityForInt(5) on the US locale as _native, and _java
shows the time taken for the ICU4J
method to be run on the US locale.

        benchmark   us linear runtime
            _java 2.27 ==============================
          _native 1.89 =========================
        vm: app_process

Change-Id: I2ca9a6636ea48bf922eceedce1cf3ef357cc4b99
5 files changed