[FIX] core.BusyIndicator: should consider window scroll position in placement
[FIX] core.BusyIndicator: should consider window scroll position in placement

- otherwise the browser scrolls itself to the top to make the whole busy
  indicator visible because it's focused. This causes the window to lose its
  previous scroll position.

Change-Id: I901f363a2a259142039629d44d77d9d36ae802dc
BCP: 1780096668

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