Move all relation queries into relation_oracle.

Move all relation queries into relation_oracle.

Move relation queries from range_query object into the relation oracle.

	* gimple-range-cache.cc (ranger_cache::ranger_cache): Call
	create_relation_oracle.
	(ranger_cache::~ranger_cache): Call destroy_relation_oracle.
	* gimple-range-fold.cc (fur_stmt::get_phi_operand): Check for
	relation oracle bnefore calling query_relation.
	(fold_using_range::range_of_phi): Likewise.
	* gimple-range-path.cc (path_range_query::~path_range_query): Set
	relation oracle pointer to NULL when done.
	* gimple-range.cc (gimple_ranger::~gimple_ranger): Likewise.
	* value-query.cc (range_query::~range_query): Ensure any
	relation oracle is destroyed.
	(range_query::query_relation): relocate to relation_oracle object.
	* value-query.h (class range_query): Adjust method proototypes.
	(range_query::create_relation_oracle): New.
	(range_query::destroy_relation_oracle): New.
	* value-relation.cc (relation_oracle::query_relation): Relocate
	from range query class.
	* value-relation.h (Call relation_oracle): New prototypes.