isl_printer_print_schedule_tree_mark: sink isl_printer_yaml_next call
isl_printer_print_schedule_tree_mark: sink isl_printer_yaml_next call

This will make it easier to extract out a common print_yaml_field
in the next commit.

Signed-off-by: Sven Verdoolaege <dd860110a62b19214c4ee03aec0abffecb4e86b8@cerebras.net>

Meinersbur/isl,Meinersbur/isl,Meinersbur/isl,Meinersbur/isl