Invalid enum value in QTextHtmlParser::tableCellBorderStyle

1. Build Qt configured with -sanitize undefined.
2. Use that to build the attached project.
3. Run the resulting program passing in the attached input file:

   ./report input.html
   

   You will see output like

   qtbase/include/QtGui/6.2.0/QtGui/private/../../../../../../../../src/qt-dev-base_svg-04.20/qtbase/src/gui/text/qtexthtmlparser_p.h:305:95: runtime error: load of value 4294967295, which is not a valid value for type 'const QTextFrameFormat::BorderStyle'
   SUMMARY: UndefinedBehaviorSanitizer: undefined-behavior qtbase/include/QtGui/6.2.0/QtGui/private/../../../../../../../../src/qt-dev-base_svg-04.20/qtbase/src/gui/text/qtexthtmlparser_p.h:305:95 in
   

Google's oss-fuzz found this as issue 31027. They will publish the details on May 18th, the latest.