[INTERNAL] sap.m.Select: validate in case the selected item is null
[INTERNAL] sap.m.Select: validate in case the selected item is null

Change-Id: Ia16fd7cd4029bab08e9ce8377e168da7424518be

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