Rectangles with certain fill patterns e.g. Qt::Dense6Pattern doesn't get generated to SVG file.

Steps to reproduce the issue:
1. Run attached test application
2. Click on "Save SVG to" button
3. Compare the QPainter and QSvgGenerator output

Expected outcome:
Also the rectangle with fill pattern is generated similarly as drawn with QPainter

Actual outcome:
Rectangle doesn't get generated to svg file