Getting namespaceId using tableId when table deleted throws wrong expection

While working on ACCUMULO-4575 I noticed that Tables.getNamespaceId(String tableId) has odd behavior. When the table is not found, it throws an illegal argument exception. In many cases what should happen in this case is that a ThriftTableNotFound exception should be thrown. Doing this will cause clients to get a clean TableNotFound exception instead of an internal server error message.

One possible solution is to make this method throw TableNotFoundException and also offer a new method that wraps, catches TableNotFoundException and throws ThriftTableNotFound.