Get rid of VEC(loaded_script_ptr)

Get rid of VEC(loaded_script_ptr)

Direct replacement with std::vector.  This allows removing a cleanup as
well.

Regtested on the buildbot.

gdb/ChangeLog:

	* auto-load.c: Don't include gdb_vecs.h, include algorithm.
	(loaded_script_ptr): Remove typedef.
	(DEF_VEC_P (loaded_script_ptr)): Remove.
	(struct collect_matching_scripts_data): Add constructor.
	<scripts_p>: Change type to (pointer to) std::vector.
	(collect_matching_scripts_data): Adjust.
	(sort_scripts_by_name): Make suitable for std::sort.
	(print_scripts): Don't sort vector, adjust to std::vector.
	(auto_load_info_scripts): Sort vectors, adjust to std::vector.