pgsql: Teach map_partition_varattnos to handle whole-row expressions.

Teach map_partition_varattnos to handle whole-row expressions.

Otherwise, partitioned tables with RETURNING expressions or subject
to a WITH CHECK OPTION do not work properly.

Amit Langote, reviewed by Amit Khandekar and Etsuro Fujita. A few
comment changes by me.

Discussion: http://postgr.es/m/9a39df80-871e-6212-0684-f93c83be4097@lab.ntt.co.jp

Branch
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master

Details
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https://git.postgresql.org/pg/commitdiff/610e8ebb0fadd7a738c2ad07fef6c5ea86b11f8d

Modified Files
--------------
src/backend/catalog/partition.c | 21 ++++++++----
src/backend/commands/tablecmds.c | 12 +++++--
src/backend/executor/nodeModifyTable.c | 4 +--
src/backend/parser/parse_utilcmd.c | 6 ++--
src/backend/rewrite/rewriteManip.c | 47 ++++++++++++++++++++++-----
src/include/catalog/partition.h | 3 +-
src/include/rewrite/rewriteManip.h | 2 +-
src/test/regress/expected/insert.out | 21 ++++++++++++
src/test/regress/expected/updatable_views.out | 26 +++++++++++++++
src/test/regress/sql/insert.sql | 13 ++++++++
src/test/regress/sql/updatable_views.sql | 27 +++++++++++++++
11 files changed, 157 insertions(+), 25 deletions(-)