[INTERNAL] sap.m.ListItemBase: Unit test for group header announcement
[INTERNAL] sap.m.ListItemBase: Unit test for group header announcement

JIRA: CPOUIFTEAMB-1030

Change-Id: I6536a6379f170d248be5036195e533312f70b521

cschuff/openui5,SAP/openui5,cschuff/openui5,cschuff/openui5,SAP/openui5,SAP/openui5,SAP/openui5