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 checkbuild
Merged-In: Ida6aac85dfb79bf8e7a3a2540e567ee211279e09
Change-Id: Ida6aac85dfb79bf8e7a3a2540e567ee211279e09
(cherry picked from commit b6826d9e)