pgsql: Fix treatment of nulls in jsonb_agg and jsonb_object_agg

Fix treatment of nulls in jsonb_agg and jsonb_object_agg

The wrong is_null flag was being passed to datum_to_json. Also, null
object key values are not permitted, and this was not being checked
for. Add regression tests covering these cases, and also add those tests
to the json set, even though it was doing the right thing.

Fixes bug #13514, initially diagnosed by Tom Lane.

Branch
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master

Details
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http://git.postgresql.org/pg/commitdiff/d9a356ff2e6bb7ed5fb1145af49fa3e51e68a98a

Modified Files
--------------
src/backend/utils/adt/jsonb.c         |   12 +++++++++---
src/test/regress/expected/json.out    |   21 ++++++++++++++++++++-
src/test/regress/expected/json_1.out  |   21 ++++++++++++++++++++-
src/test/regress/expected/jsonb.out   |   19 ++++++++++++++++++-
src/test/regress/expected/jsonb_1.out |   19 ++++++++++++++++++-
src/test/regress/sql/json.sql         |   13 +++++++++++--
src/test/regress/sql/jsonb.sql        |   12 +++++++++++-
7 files changed, 107 insertions(+), 10 deletions(-)