This removes a use of the queue data structure (common/queue.h) from
remote.c.

The queue is replaced with a std::vector.  A queue was not needed, as
the code never de-queued items.

This removes quite a bit of boilerplate code, mostly involved with
marshalling arguments to be passed through the queue iterator.

Tested by the buildbot.

gdb/ChangeLog
2018-06-10  Tom Tromey  <tom@tromey.com>

	* remote.c (stop_reply_p): Remove typedef.  Don't declare queue.
	(class remote_state) <stop_reply_queue>: Now std::vector.
	(remote_state::~remote_state)
	(remote_target::stop_reply_queue_length): Update.
	(struct queue_iter_param, remove_child_of_pending_fork)
	(struct check_pending_event_prevents_wildcard_vcont_callback_data)
	(check_pending_event_prevents_wildcard_vcont_callback)
	(remove_stop_reply_for_inferior)
	(remove_stop_reply_of_remote_state)
	(remote_notif_remove_once_on_match)
	(stop_reply_match_ptid_and_ws)
	(remote_kill_child_of_pending_fork): Remove.
	(remote_target::remove_new_fork_children)
	(remote_target::check_pending_events_prevent_wildcard_vcont)
	(remote_target::discard_pending_stop_replies)
	(remote_target::discard_pending_stop_replies_in_queue)
	(remote_target::remote_notif_remove_queued_reply)
	(remote_target::queued_stop_reply)
	(remote_target::push_stop_reply, remote_target::peek_stop_reply)
	(remote_target::wait, remote_target::kill_new_fork_children)
	(remote_target::async): Update.