re PR c++/12850 (memory consumption for heavy template instantiations tripled since 3.3)

	PR c++/12850
	* cgraph.c (cgraph_remove_node): Clear out saved/insns/arguments and
	initial pointers.
	* cgraphunit.c (cgraph_finalize_function): Clear out DECL_SAVED_INSNS
	for functions that will be only inlined.
	(cgraph_mark_function_to_output): Likewise.
	(cgraph_expand_function): Sanity check that DECL_DEFER_OUTPUT is clear;
	do not clear function body.
	* tree-optimize.c (clear_decl_rtl): Use decl_function_context.
	(tree_rest_of_compilation): Reorganize the logic releasing function
	body to use callgraph datastructure.

From-SVN: r76822