Undo stack shows unwanted results with QHeaderView stretchLastSection set to true

When the stretchLastSection property of QHeaderView is set to true the QHeaderView::sectionResized reports incorrect size values that make the undo stack behave incorrectly.

This can be reproduced with the attached example by shortening the first column. Then the QHeaderView::sectionResized reports the last section values and the undo stack is no longer usable.