Convert IDN to use ICU4j instead of ICU4c.

Apache harmony tests still pass after this change, and
new tests have been added to verify that this meets the
specification defined in

The benchmarks below show the performance penalty from not doing
this natively.
          benchmark   us linear runtime
        JavaToAscii 59.6 =========================
      JavaToUnicode 68.9 ==============================
      NativeToAscii 11.2 ====
    NativeToUnicode 13.8 ======

Change-Id: Ie3fd1d439d9fc2651f5f1773676d12409c430c83
6 files changed