Fix copying of clone_info while reshaping clone tree.

Fix copying of clone_info while reshaping clone tree.

2020-11-04  Jan Hubicka  <hubicka@ucw.cz>

	PR ipa/97695
	* cgraph.c (cgraph_edge::redirect_call_stmt_to_callee): Fix ICE with
	in dumping code.
	(cgraph_node::remove): Save clone info before releasing it and pass it
	to unregister.
	* cgraph.h (symtab_node::unregister): Add clone_info parameter.
	(cgraph_clone::unregister): Likewise.
	* cgraphclones.c (cgraph_node::find_replacement): Copy clone info
	* symtab-clones.cc (clone_infos_t::duplicate): Remove.
	(clone_info::get_create): Simplify.
	* symtab.c (symtab_node::unregister): Pass around clone info.
	* varpool.c (varpool_node::remove): Update.