Set a minimum height on line boxes if no text is placed
Set a minimum height on line boxes if no text is placed

Prevents an infinite recursion in cases where the height of the
line is zero, causing the split text to continually place in the
same location.

WIP: Would it be better to shift the line down instead to prevent
empty frames?

dompdf/dompdf,BrunoDeBarros/dompdf,BrunoDeBarros/dompdf,nathanntg/dompdf,nathanntg/dompdf,dompdf/dompdf