Fix handling of type tuple associated with a temp relation. We have

Fix handling of type tuple associated with a temp relation.  We have
to apply the tempname->realname mapping to type name lookup as well
as relation name lookup, else the type tuple will not be found when
wanted.  This fixes bugs like this one:
create temp table foo (f1 int);
select foo.f2 from foo;
ERROR:  Unable to locate type name 'foo' in catalog