Include Test Case List from CTS Project

Bug 2732160

Have the cts.mk include the test case list from CTS rather
than defining it in cts.mk. This permits CTS developers to
add new packages and applications without having to submit
multiple project changes to both the CTS and build projects
everytime.

Change-Id: I63d90ac4f5d9fc9a9aa0ff79a8bf9dfb1a79c822