pgsql: Change cardinality() into a C-code function, instead of a

Log Message:
-----------
Change cardinality() into a C-code function, instead of a SQL-language
alias for array_length(v,1). The efficiency gain here is doubtless
negligible --- what I'm interested in is making sure that if we have
second thoughts about the definition, we will not have to force a
post-beta initdb to change the implementation.

Modified Files:
--------------
pgsql/src/backend/utils/adt:
arrayfuncs.c (r1.153 -> r1.154)
(http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/src/backend/utils/adt/arrayfuncs.c?r1=1.153&r2=1.154)
pgsql/src/include/catalog:
catversion.h (r1.527 -> r1.528)
(http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/src/include/catalog/catversion.h?r1=1.527&r2=1.528)
pg_proc.h (r1.539 -> r1.540)
(http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/src/include/catalog/pg_proc.h?r1=1.539&r2=1.540)
pgsql/src/include/utils:
array.h (r1.74 -> r1.75)
(http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/src/include/utils/array.h?r1=1.74&r2=1.75)