[INTERNAL][FIX] sap.m.ComboBoxBase: avoid unnecessary re-rendering
[INTERNAL][FIX] sap.m.ComboBoxBase: avoid unnecessary re-rendering

Avoid unnecessary re-rendering of the input field when an item is
inserted via .insertItem().

Change-Id: I303dabd7f166ac9bf09bbc5dac856cc2cad02ab3

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