[INTERNAL] ComboBox: fixed QUnit test issue (popup doesn't open)
[INTERNAL] ComboBox: fixed QUnit test issue (popup doesn't open)

Change-Id: Ibe97089329db320d6c249a16cae7c80d4183de4d

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