Add CleanSpec.mk to frameworks/rs and add support for building all tests.

Without the tests/Android.mk, each test would need to be individually built
using mm in the separate directories. I also added a CleanSpec.mk to properly
get rid of all the stale build-related files from the moved tests.

Change-Id: I248d6f1252b3b6e02874917194c5e8233e70edef
2 files changed