Also start the deprecation for BUILD_HOST_TEST_CONFIG and
BUILD_TARGET_TEST_CONFIG, which have no users.
Bug: 130720555
Bug: 130723115
Bug: 130734993
Test: treehugger
Test: Add entries to DEFAULT_ERROR / OBSOLETE to manually test behavior
Change-Id: Icfdff43a29b6512494d44b9be11d178333505010