Move out all framework-tests classes.

Previously tests/framework-tests contained a quarantined set of test classes
that needed access to package-private framework api. Running these tests
normally would cause the dalvik verifier to throw errors.

runtest now has support for turning off the dalvik verifier for frameworks
tests, so move this tests into their recommended location, close to the source
being tested.

Also move policy source into a 'src' folder to accommodate the tests move.

Change-Id: I62f839da185a55bc553b653bf583fd99da438512