pgsql: Remove es_result_relation_info from EState.

Remove es_result_relation_info from EState.

Maintaining 'es_result_relation_info' correctly at all times has become
cumbersome, especially with partitioning where each partition gets its
own result relation info. Having to set and reset it across arbitrary
operations has caused bugs in the past.

This changes all the places that used 'es_result_relation_info', to
receive the currently active ResultRelInfo via function parameters
instead.

Author: Amit Langote
Discussion: https://www.postgresql.org/message-id/CA%2BHiwqGEmiib8FLiHMhKB%2BCH5dRgHSLc5N5wnvc4kym%2BZYpQEQ%40mail.gmail.com

Branch
------
master

Details
-------
https://git.postgresql.org/pg/commitdiff/a04daa97a4339c38e304cd6164d37da540d665a8

Modified Files
--------------
src/backend/commands/copy.c | 19 +--
src/backend/commands/tablecmds.c | 2 -
src/backend/executor/execIndexing.c | 9 +-
src/backend/executor/execMain.c | 4 -
src/backend/executor/execReplication.c | 24 ++--
src/backend/executor/execUtils.c | 1 -
src/backend/executor/nodeModifyTable.c | 200 +++++++++++++------------------
src/backend/replication/logical/worker.c | 17 +--
src/include/executor/executor.h | 19 ++-
src/include/executor/nodeModifyTable.h | 4 +-
src/include/nodes/execnodes.h | 1 -
src/test/regress/expected/insert.out | 4 +-
src/test/regress/sql/insert.sql | 4 +-
13 files changed, 131 insertions(+), 177 deletions(-)