Forcing query execution in SQLiteDatabase.query

The issue is that our code often "executes" a query
on a background thread but iterates over the cursor
on the UI thread.  Since we actually do the fetch
on moveToFirst or moveToNext, the query is in reality
often run on the UI thread and causes an ANR.

Change-Id: Ia561135e974a44ad3e3774ecb23c6a3d0fc38176