[INTERNAL] sap.ui.core.Popup: improve rendering performance
[INTERNAL] sap.ui.core.Popup: improve rendering performance

- Avoid uses of the jQuery's hide() method

The jQuery hide() method is doing much more magic behind the scenes than
developers expect and that magic decreases the rendering performance.

Change-Id: Ided4ac61a2c28761ad4c37644d3e964096fb4534

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