pgsql: Forbid SJE with result relation

Forbid SJE with result relation

The target relation for INSERT/UPDATE/DELETE/MERGE has a different behavior
than other relations in EvalPlanQual() and RETURNING clause.  This is why we
forbid target relation to be either source or target relation in SJE.
It's not clear if we could ever support this.

Reported-by: Alexander Lakhin
Discussion: https://postgr.es/m/b9e8f460-f9a6-0e9b-e8ba-60d59f0bc22c%40gmail.com

Branch
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master

Details
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https://git.postgresql.org/pg/commitdiff/8c441c082797f22ae96f50b641a8ef3f65c92b8d

Modified Files
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src/backend/optimizer/plan/analyzejoins.c     | 11 ++++
src/test/regress/expected/join.out            | 76 +++++++++++++++++----------
src/test/regress/expected/updatable_views.out | 17 +++---
src/test/regress/sql/join.sql                 | 28 +++++-----
4 files changed, 84 insertions(+), 48 deletions(-)