analyzer: eliminate non-deterministic behavior

analyzer: eliminate non-deterministic behavior

This patch is a followup to the previous one, eliminating
non-determinism in the behavior of the analyzer (rather than just in
the logs), by sorting whenever the result previously depended on
pointer values.  Tested as per the previous patch.

gcc/analyzer/ChangeLog:
	* constraint-manager.cc (svalue_cmp_by_ptr): Delete.
	(equiv_class::canonicalize): Use svalue::cmp_ptr_ptr instead.
	(equiv_class_cmp): Eliminate pointer comparison.
	* diagnostic-manager.cc (dedupe_key::comparator): If they are at
	the same location, also compare epath ength and pending_diagnostic
	kind.
	* engine.cc (readability_comparator): If two path_vars have the
	same readability, then impose an arbitrary ordering on them.
	(worklist::key_t::cmp): If two points have the same plan ordering,
	continue the comparison.  Call sm_state_map::cmp rather than
	comparing hash values.
	* program-state.cc (sm_state_map::entry_t::cmp): New.
	(sm_state_map::cmp): New.
	* program-state.h (sm_state_map::entry_t::cmp): New decl.
	(sm_state_map::elements): New.
	(sm_state_map::cmp): New.