src/svgtiny_css.c: fix lwc/dom string comparison in node_has_name()

src/svgtiny_css.c: fix lwc/dom string comparison in node_has_name()

The node_has_name() function was calling lwc_string_isequal() to test
the universal selector (a dom_string) against the given node name (an
lwc_string). Instead, it should be using dom_string_lwc_isequal(),
which is designed to do exactly that. Thanks to Michael Drake for the
suggestion.