pgsql: Revert cascading of JSON_TABLE's ON ERROR

Revert cascading of JSON_TABLE's ON ERROR

86ab7f4c721d commit made the table-level ON ERROR clause serve as the default
ON ERROR for columns lacking their own, so that a top-level ERROR ON ERROR
turned per-column evaluation errors into hard errors.

The SQL standard does mandate this cascade, but introducing it should be
a deliberate, separately-documented change, so restore the previous
behavior for now. This also reverts the paired ruleutils.c logic that
deparsed a column's behavior against an ERROR default: that dropped an
explicit ERROR ON EMPTY from a dumped view, and otherwise emitted a
redundant NULL ON EMPTY.

Reported-by: Thom Brown <thom(at)linux(dot)com>
Discussion: https://postgr.es/m/CAA-aLv7aZGSExnbjJRw8eKkoXbu34TdoKLLA2gPye3aHjO5OSA@mail.gmail.com

Branch
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master

Details
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https://git.postgresql.org/pg/commitdiff/af6fad879fbf9b542cfde05c52695c9dffa6bb47

Modified Files
--------------
src/backend/parser/parse_jsontable.c | 13 +++---------
src/backend/utils/adt/ruleutils.c | 4 ----
src/test/regress/expected/sqljson_jsontable.out | 27 ++++++++++++++++++++++++-
src/test/regress/sql/sqljson_jsontable.sql | 15 ++++++++++++++
4 files changed, 44 insertions(+), 15 deletions(-)