Make transitive relations an oracle option

Make transitive relations an oracle option

This patch makes processing of transitive relations configurable at
dom_oracle creation.

	* tree-vrp.cc (execute_fast_vrp): Do not use transitive relations.
	* value-query.cc (range_query::create_relation_oracle): Add
	parameter to enable transitive relations.
	* value-query.h (range_query::create_relation_oracle): Likewise.
	* value-relation.h (dom_oracle::dom_oracle): Likewise.
	* value-relation.cc (dom_oracle::dom_oracle): Likewise.
	(dom_oracle::register_transitives): Check transitive flag.