Incorrect text rendering when using <font> and <glyph> elements

Open fonts-glyph-201-t.svg or fonts-glyph-202-t.svg from the test suite and see their renderings:

• Qt renders the text "fjord" as "fjjord", i.e. it adds a redundant "j"
• They show white strokes around letters where shapes overlap. Qt shows them in different places than seen in the test suite's .png files, i.e they can be seen in the respective other line.