Use `temp_directory` in favor of `tempfile` in the PDF embedded files testcase.
Use `temp_directory` in favor of `tempfile` in the PDF embedded files testcase.

andrewleech/WeasyPrint,marclaporte/WeasyPrint,Kozea/WeasyPrint,Kozea/WeasyPrint,andrewleech/WeasyPrint,prepare/TestWeasyPrint,prepare/TestWeasyPrint,jasco/WeasyPrint,jasco/WeasyPrint,marclaporte/WeasyPrint