Add an ART test target exercising Generational CC collection.

Add an `art-generational-cc` test target runing ART run-tests and
gtests in Generational Concurrent Copying (CC) Garbage Collection
mode (on host).

Test: art/test/testrunner/run_build_test_target.py art-generational-cc
Bug: 67628039
Change-Id: Id1a778394b0f30d528606aef3d5e33b41e3c8651