pg_dump: Add table qualifications to some tags

Some object types have names that are only unique for one table.  But
for those we generally didn't put the table name into the dump TOC tag.
So it was impossible to identify these objects if the same name was used
for multiple tables.  This affects policies, column defaults,
constraints, triggers, and rules.

Fix by adding the table name to the TOC tag, so that it now reads
"$schema $table $object".

Reviewed-by: Michael Paquier <michael.paquier@gmail.com>