After commit f3dae2ae58, the primary purpose of separating the
pg_set_*_stats() from the pg_restore_*_stats() variants was
eliminated.
Leave pg_restore_relation_stats() and pg_restore_attribute_stats(),
which satisfy both purposes, and remove pg_set_relation_stats() and
pg_set_attribute_stats().
Reviewed-by: Corey Huinker <corey.huinker@gmail.com>
Discussion: https://postgr.es/m/1457469.1740419458@sss.pgh.pa.us
a5cbdeb98a