Move to an always available relation oracle.

Move to an always available relation oracle.

This eliminates the need to check if the relation oracle pointer is NULL
before every call by providing a default oracle which does nothing.
REmove unused routines, and Unify register_relation method names.

	* gimple-range-cache.cc (ranger_cache::dump_bb): Remove check for
	NULL oracle pointer.
	(ranger_cache::fill_block_cache): Likewise.
	* gimple-range-fold.cc (fur_stmt::get_phi_operand): Likewise.
	(fur_depend::fur_depend): Likewise.
	(fur_depend::register_relation): Likewise, use qury_relation.
	(fold_using_range::range_of_phi): Likewise.
	(fold_using_range::relation_fold_and_or): Likewise.
	* gimple-range-fold.h (fur_source::m_oracle): Delete.  Oracle
	can be accessed dirctly via m_query now.
	* gimple-range-path.cc (path_range_query::path_range_query):
	Adjust for oracle reference pointer.
	(path_range_query::compute_ranges): Likewise.
	(jt_fur_source::jt_fur_source): Adjust for no m_oracle member.
	(jt_fur_source::register_relation): Do not check for NULL
	pointer.
	(jt_fur_source::query_relation): Likewise.
	* gimple-range.cc (gimple_ranger::gimple_ranger):  Adjust for
	reference pointer.
	* value-query.cc (default_relation_oracle): New.
	(range_query::create_relation_oracle): Relocate from header.
	Ensure not being added to global query.
	(range_query::destroy_relation_oracle): Relocate from header.
	(range_query::range_query): Initailize to default oracle.
	(ange_query::~range_query): Call destroy_relation_oracle.
	* value-query.h (class range_query): Adjust prototypes.
	(range_query::create_relation_oracle): Move to source file.
	(range_query::destroy_relation_oracle): Move to source file.
	* value-relation.cc (relation_oracle::validate_relation): Delete.
	(relation_oracle::register_stmt): Rename to register_relation.
	(relation_oracle::register_edge): Likewise.
	* value-relation.h (register_stmt): Rename to register_relation and
	provide default function in base class.
	(register_edge): Likewise.
	(relation_oracle::validate_relation): Delete.
	(relation_oracle::query_relation): Provide default in base class.
	(relation_oracle::dump): Likewise.
	(relation_oracle::equiv_set): Likewise.
	(default_relation_oracle): New extenal reference.
	(partial_equiv_set, add_partial_equiv): Move to protected.