Move global range code to value-query.cc.

Move global range code to value-query.cc.

This patch moves all the global range code from gimple-range.cc into
value-query.cc.  It also moves get_range_info and get_ptr_nonnull from
tree-ssanames.c into their only uses, and removes external access to them.

gcc/ChangeLog:

	* gimple-range.cc (get_range_global): Move to value-query.cc.
	(gimple_range_global): Same.
	(get_global_range_query): Same.
	(global_range_query::range_of_expr): Same.
	* gimple-range.h (class global_range_query): Move to
	value-query.h.
	(gimple_range_global): Same.
	* tree-ssanames.c (get_range_info): Move to value-query.cc.
	(get_ptr_nonnull): Same.
	* tree-ssanames.h (get_range_info): Remove.
	(get_ptr_nonnull): Remove.
	* value-query.cc (get_ssa_name_range_info): Move from
	tree-ssanames.c.
	(get_ssa_name_ptr_info_nonnull): Same.
	(get_range_global): Move from gimple-range.cc.
	(gimple_range_global): Same.
	(get_global_range_query): Same.
	(global_range_query::range_of_expr): Same.
	* value-query.h (class global_range_query): Move from
	gimple-range.h.
	(gimple_range_global): Same.