pgsql: Fix replica identity check for INSERT ON CONFLICT DO UPDATE.

Fix replica identity check for INSERT ON CONFLICT DO UPDATE.

If an INSERT has an ON CONFLICT DO UPDATE clause, the executor must
check that the target relation supports UPDATE as well as INSERT. In
particular, it must check that the target relation has a REPLICA
IDENTITY if it publishes updates. Formerly, it was not doing this
check, which could lead to silently breaking replication.

Fix by adding such a check to CheckValidResultRel(), which requires
adding a new onConflictAction argument. In back-branches, preserve ABI
compatibility by introducing a wrapper function with the original
signature.

Author: Zhijie Hou <houzj.fnst@fujitsu.com>
Reviewed-by: Ashutosh Bapat <ashutosh.bapat.oss@gmail.com>
Reviewed-by: Dean Rasheed <dean.a.rasheed@gmail.com>
Tested-by: Chao Li <li.evan.chao@gmail.com>
Discussion: https://postgr.es/m/OS3PR01MB57180C87E43A679A730482DF94B62@OS3PR01MB5718.jpnprd01.prod.outlook.com
Backpatch-through: 13

Branch
------
REL_16_STABLE

Details
-------
https://git.postgresql.org/pg/commitdiff/0c4d5a45dbd7d11c9ddff4f7cf4dae3940b083be

Modified Files
--------------
src/backend/executor/execMain.c           | 23 ++++++++++++++++++++++-
src/backend/executor/execPartition.c      |  8 ++++++--
src/backend/executor/nodeModifyTable.c    |  3 ++-
src/include/executor/executor.h           |  2 ++
src/test/regress/expected/publication.out | 23 +++++++++++++++++++++++
src/test/regress/sql/publication.sql      | 26 ++++++++++++++++++++++++++
6 files changed, 81 insertions(+), 4 deletions(-)