Use ICU in libandroidicu

libicuuc and libicui18n are moved into APEX, but
they have no stable ABI due to the version suffix.

Use libandroidicu which provides stable symbol.
See http://go/apex-stable-icu4c-interface for the design.
See http://aosp/801855 for libandroidicu implementation.

Bug: 117094880
Test: m
Change-Id: I559d1854a530b5280a29c4f54a6543402ab0b317
(cherry picked from commit a4a72482)