8004073: Implement C2 Ideal node specific dump() method Summary: add Node::dump_rel() to dump a node and its related nodes (the notion of "related" depends on the node at hand); add Node::dump_comp() to dump a node in compact representation; add Node::dump_rel_comp() to dump a node and its related nodes in compact representation; add the required machinery; extend some C2 IR nodes with compact and related dumping Reviewed-by: kvn, roland