Reland "First pass at creating PRODUCT_HOST_PACKAGES"

Adds icu-data_host_runtime_apex to fix unbundled builds which pull it in
via PRODUCT_PACKAGES, but are missing packages that would pull it in via
PRODUCT_HOST_PACKAGES.

Test: build/soong/build_test.bash
Test: in ub-timezonedata-master; tapas TimeZoneData; m
Change-Id: I1583c7582b386c3e8478711cb1df340518d763c1
Merged-In: I1583c7582b386c3e8478711cb1df340518d763c1