Clean up new SQLite APIs

Bug: 279043253

This cleans up some documentation and adds two missing exceptions in
preparation for making the APIs public.

Test: atest
 * android.database.sqlite.SQLiteRawStatementTest
 * android.database.sqlite.cts.SQLiteDatabaseTest

Change-Id: I939fea6ffa4d7bb4d6ecf89a4e2d8e88ee10f878