"Move core-icu4j into i18n APEX" Attempt 2

This reverts commit b72f1e1a8ac59c60854a8de46713955c3549c5d3.
Reland https://r.android.com/1284676

Bug: 138994281
Test: core-icu4j observed in i18n APEX
Change-Id: If773316261fb1f5fb37b56c5233efcc4a434354a
diff --git a/target/product/base_system.mk b/target/product/base_system.mk
index 3e5d3a3..5c88ae8 100644
--- a/target/product/base_system.mk
+++ b/target/product/base_system.mk
@@ -320,6 +320,7 @@
     $(ART_APEX_JARS) \
     framework-minus-apex \
     ext \
+    com.android.i18n:core-icu4j \
     telephony-common \
     voip-common \
     ims-common \