pgsql: SQL/JSON: Fix JSON_TABLE() column deparsing

SQL/JSON: Fix JSON_TABLE() column deparsing

The deparsing code in get_json_expr_options() unnecessarily emitted
the default column-specific ON ERROR / EMPTY behavior when the
top-level ON ERROR behavior in JSON_TABLE was set to ERROR. Fix that
by not overriding the column-specific default, determined based on
the column's JsonExprOp in get_json_table_columns(), with
JSON_BEHAVIOR_ERROR when that is the top-level ON ERROR behavior.

Note that this only removes redundancy; the current deparsing output
is not incorrect, just redundant.

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

Branch
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master

Details
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https://git.postgresql.org/pg/commitdiff/68222851d5a8d2ca152a97ee69fe18a95970ed20

Modified Files
--------------
src/backend/utils/adt/ruleutils.c | 8 ++++----
src/test/regress/expected/sqljson_jsontable.out | 18 ++++++++++++++++++
src/test/regress/sql/sqljson_jsontable.sql | 5 +++++
3 files changed, 27 insertions(+), 4 deletions(-)