Remove mockito, and replace with mock

There are unit tests in trove which are dependent on mockito.
This fixes them to use the standard mock library which is a part
of global_requirements.

Co-Authored-By: Justin Hopper <justin.hopper@hp.com>
Implements-bp: remove-mockito
Change-Id: Ic030cc846d9e7d0c9077240b0fac90f4f66a5a42