A couple of marginal performance hacks for the information_schema views:

A couple of marginal performance hacks for the information_schema views:
replace the old recursive-SQL-function implementation of _pg_keysequal()
with use of the built-in array containment operators, and change
table_constraints' UNION to UNION ALL.  Per discussion with Octavio Alvarez.

initdb not forced since this doesn't affect results, but you'd need to
initdb or reload the information_schema to see the new definitions.