[INTERNAL][FIX] sap.m.ComboBox: models cleanup of unit test
[INTERNAL][FIX] sap.m.ComboBox: models cleanup of unit test

Change-Id: I70a51a73a7457da31c1683d774f78de90aa317ee

SAP/openui5,olirogers/openui5,SAP/openui5,SAP/openui5,SQCLabs/openui5,SQCLabs/openui5,olirogers/openui5,nzamani/openui5,cschuff/openui5,cschuff/openui5,SAP/openui5,nzamani/openui5,olirogers/openui5,SQCLabs/openui5,nzamani/openui5,cschuff/openui5