sched: Change return type of predicate functions from int to bool

sched: Change return type of predicate functions from int to bool

Also change some internal variables to bool.

gcc/ChangeLog:

	* sched-int.h (struct haifa_sched_info): Change can_schedule_ready_p,
	scehdule_more_p and contributes_to_priority indirect frunction
	type from int to bool.
	(no_real_insns_p): Change return type from int to bool.
	(contributes_to_priority): Ditto.
	* haifa-sched.cc (no_real_insns_p): Change return type from
	int to bool and adjust function body accordingly.
	* modulo-sched.cc (try_scheduling_node_in_cycle): Change "success"
	variable type from int to bool.
	(ps_insn_advance_column): Change return type from int to bool.
	(ps_has_conflicts): Ditto. Change "has_conflicts"
	variable type from int to bool.
	* sched-deps.cc (deps_may_trap_p): Change return type from int to bool.
	(conditions_mutex_p): Ditto.
	* sched-ebb.cc (schedule_more_p): Ditto.
	(ebb_contributes_to_priority): Change return type from
	int to bool and adjust function body accordingly.
	* sched-rgn.cc (is_cfg_nonregular): Ditto.
	(check_live_1): Ditto.
	(is_pfree): Ditto.
	(find_conditional_protection): Ditto.
	(is_conditionally_protected): Ditto.
	(is_prisky): Ditto.
	(is_exception_free): Ditto.
	(haifa_find_rgns): Change "unreachable" and "too_large_failure"
	variables from int to bool.
	(extend_rgns): Change "rescan" variable from int to bool.
	(check_live): Change return type from
	int to bool and adjust function body accordingly.
	(can_schedule_ready_p): Ditto.
	(schedule_more_p): Ditto.
	(contributes_to_priority): Ditto.