1. Create QFileDialog with several different filters. (avi, mpeg2)
2. Enter test.avi as file name
3. Select some different filter from the list (mpeg2)
-> Filename should be automatically changed to test.mpeg2 but it remains the same no matter what filter is selected from the list.
|For Gerrit Dashboard: QTBUG-31381|
|58161,1||Windows save file dialog: Set default suffix only once.||release||qt/qtbase||Status: MERGED||+2||0|