SQL/JSON: Respect OMIT QUOTES when RETURNING domains over jsonb

SQL/JSON: Respect OMIT QUOTES when RETURNING domains over jsonb

populate_domain() didn't take into account the omit_quotes flag passed
down to json_populate_type() by ExecEvalJsonCoercion() and that led
to incorrect behavior when the RETURNING type is a domain over
jsonb.  Fix that by passing the flag by adding a new function
parameter to populate_domain().

Reported-by: Jian He <jian.universality@gmail.com>
Discussion: https://postgr.es/m/CACJufxEo4sUjKCYtda0_qt9tazqqKPmF1cqhW9KBOUeJFqQd2g@mail.gmail.com
Backpatch-through: 17