Clean up BT stress tests.

Make ConnectPanReceiver a child of ConnectProfileReceiver, check if a
profile proxy is null before trying to connect.  Change log output in
bluetooth.  Remove some oververbose parameters from test runner. Make
the setup for the tests more consistent (delete pairings, etc).

Most of this work has been done to facilitate the tests created for
trade federation.

Change-Id: I7350d308b5d09c2052e0a3f3308a69c564ba4d74