Removed all references to the 'No Rex R1rho off res' model in the system tests.
In addition, the Relax_disp.test_convert_no_rex system test has been deleted as it no longer has a
purpose. For the Relax_disp.test_model_nesting_and_param system test, to allow this to work the
cdp.exp_type_list list is set to EXP_TYPE_LIST.
