pgsql: Fix interaction of triggers, partitioning, and EXPLAIN ANALYZE.

Fix interaction of triggers, partitioning, and EXPLAIN ANALYZE.

Add a new EState member es_leaf_result_relations, so that the trigger
code knows about ResultRelInfos created by tuple routing. Also make
sure ExplainPrintTriggers knows about partition-related
ResultRelInfos.

Etsuro Fujita, reviewed by Amit Langote

Discussion: http://postgr.es/m/57163e18-8e56-da83-337a-22f2c0008051@lab.ntt.co.jp

Branch
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REL_10_STABLE

Details
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https://git.postgresql.org/pg/commitdiff/d4b42e5215fae85e2ae473ba4957705f4c9861e9

Modified Files
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src/backend/commands/copy.c | 110 +++++++++++++++++----------------
src/backend/commands/explain.c | 15 ++++-
src/backend/executor/execMain.c | 45 ++++++++++----
src/backend/executor/execUtils.c | 5 ++
src/backend/executor/nodeModifyTable.c | 1 +
src/include/executor/executor.h | 1 +
src/include/nodes/execnodes.h | 3 +
7 files changed, 115 insertions(+), 65 deletions(-)