libctf: dump: support non-root type dumping

Use the recently-added ctf_type_iter_all function to iterate over
non-root types, too, indicating them via {....} surrounding the type
description in the dump.

libctf/
	* ctf-dump.c (ctf_dump): Use ctf_type_iter_all to dump types, not
	ctf_type_iter.
	(ctf_dump_type): Pass down the flag from ctf_type_iter_all.
	(ctf_dump_format_type): Add non-root-type { } notation.
	Add root flag to prototype.
	(ctf_dump_label): Adjust accordingly.
	(ctf_dump_objts): Likewise.
	(ctf_dump_var): Likewise.