Update Junit from 4.13 to Latest version 5.6.2

As of current upgrade, we would want to upgrade JunitTest from 4.13 to latest version 5.62, and also latest versions of Hamcrest, Mockito, and PowerMock.

Update all tests in Core to run with the latest versions.

Upgrade Mockito-Core  from 2.28.2 to <version>3.0.0</version>

  This link May be of help https://junit.org/junit5/docs/current/release-notes/index.html#release-notes-5.6.2