move TS_EXP to be a substructure of TS_TYPED
gcc/
	* tree.h (struct tree_exp): Inherit from struct tree_typed.
	* tree.c (initialize_tree_contains_struct): Mark TS_EXP as TS_TYPED
	instead of TS_COMMON.

gcc/lto/
	* lto.c (lto_ft_typed): New function.
	(lto_ft_common): Call it.
	(lto_ft_constructor): Likewise.
	(lto_ft_expr): Likewise.
	(lto_fixup_prevailing_decls): Check for TS_COMMON before accessing
	TREE_CHAIN.

From-SVN: r174192