gdb: change some int to bool in infrun.c

gdb: change some int to bool in infrun.c

Change these int-used-as-a-bool to bool.  I searched for "static int" in
that file and changed what I found.

gdb/ChangeLog:

	* infrun.c (currently_stepping): Change int to bool
	(maybe_software_singlestep): Likewise.
	(show_stop_on_solib_events): Likewise.
	(stepping_past_nonsteppable_watchpoint): Likewise.
	(displaced_step_in_progress_any_inferior): Likewise.
	(displaced_step_in_progress_thread): Likewise.
	(keep_going_stepped_thread): Likewise.
	(thread_still_needs_step_over): Likewise.
	(start_step_over): Likewise.
	(do_target_resume): Likewise.
	(resume_1): Likewise.
	(clear_proceed_status): Likewise.
	(thread_still_needs_step_over_bp): Likewise.
	(proceed): Likewise.
	(switch_back_to_stepped_thread): Likewise.
	(adjust_pc_after_break): Likewise.
	(stepped_in_from): Likewise.
	(handle_stop_requested): Likewise.
	(handle_syscall_event): Likewise.
	(handle_no_resumed): Likewise.
	(handle_inferior_event): Likewise.
	(finish_step_over): Likewise.
	(handle_signal_stop): Likewise.
	(process_event_stop_test): Likewise.

Change-Id: I897527c4a3da5e647f9d97f7d4477649985b8b77