Add script to expedite running passing tests

Developers can run this script from within a shell where they have
source'd build/envsetup.sh and lunched a target.  It builds, installs,
and runs whitelisted test packages.

Bug: None
Test: This script is useful for iterating rapidly on unittests.

Change-Id: I44c32a0f75da1be2c69a8b1a67c0080a68def738