Record nodes as dead in Node::destruct() if their index cannot be directly
reclaimed. This prevents the "Live Node limit exceeded limit" assertion failure
by improving the accuracy of Compile::live_nodes() when "hook" nodes in
ConvI2LNode::Ideal() are created and deleted non-consecutively.
This addition might result in multiple calls to compile::record_dead_node() for
the same node (e.g. from PhaseIdealLoop::spinup()), but this is safe, as
compile::record_dead_node() is idempotent.
Reviewed-by: neliasso, thartmann
