Fix incorrect declarations of variadic pg_get_*_ddl() functions.

Fix incorrect declarations of variadic pg_get_*_ddl() functions.

The final parameter of an ordinary variadic function should be an
array type.  CREATE FUNCTION won't accept a declaration that isn't
like that, but it's possible to put an incorrect combination into a
pg_proc.dat entry.  Sadly, the opr_sanity test that was supposed to
check that is broken and does not report functions with non-array
final parameters.  This allowed exactly such a thinko to sneak into
the recently-added pg_get_*_ddl() functions: their last argument
should be declared text[] but was declared text.  (We'd probably
have noticed eventually, when somebody tried to actually pass a
variadic array to one of those functions.  But their regression
tests do not do that.)

Fix those functions, and fix the opr_sanity test so we'll notice
next time.  Bump catversion for new pg_proc contents.

Author: Chao Li <li.evan.chao@gmail.com>
Reviewed-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/D41A334E-ED9E-42EE-830D-28D4D36E9317@gmail.com