libctf, dump: do not emit size or alignment if it would error

libctf, dump: do not emit size or alignment if it would error

When we dump normal types, we emit their size and/or alignment:
but size and alignment dumping can return errors if the type is
part of a chain that terminates in a forward.

Emitting 0xffffffff as a size or alignment is unhelpful, so simply
skip emitting this info for any type for which size or alignment
checks return an error, no matter what the error is.

libctf/ChangeLog
2021-03-25  Nick Alcock  <nick.alcock@oracle.com>

	* ctf-dump.c (ctf_dump_format_type): Don't emit size or alignment
	on error.