-> Define separate test cases for downgrade with initial and non-initial
MGMD restart.

-> Modify test functions to handle initial and non-initial MGMD restarts
based on test case property InitialMgmdRestart.
If InitialMgmdRestart is not set, it is considered to be 0 (non-initial)
by default.
--initial is set to 1 by adding the following while defining the testcase:
 TC_PROPERTY("InitialMgmdRestart", 1);

-> Define functions to check if an upgrade test case is actually doing an
upgrade or downgrade.

-> Add the new test cases to the test suite

Reviewed by: Mauritz Sundell <mauritz.sundell@oracle.com>