QtSvg parser does not handle nested svg elements correctly

The SVG Tiny 1.2 standard specifies that nested <svg> elements are not allowed, and they should be treated as an unsupported elements

https://www.w3.org/TR/SVGTiny12/intro.html#TermSVGDocumentFragment

The parser does not handle this case well, because it stops parsing once it reaches the end of the first <svg> element. This means if an SVG file contains nested <svg> elements, the parser will stop in the middle, and mark it as done. 

The two attached files can be used with the Svg Viewer to demonstrate this issue. The "struct-svg-203-t.svg" is from the SVG Tiny 1.2 test suite, where the "Revision 1.5" text is not printed.

The other file is written by me, where the middle red rectangle is enclosed in an <svg> element, this causes the Svg viewer to skip displaying both the red and green rectangles.