pgsql: Even if some partitions are foreign, allow tuple routing.

Even if some partitions are foreign, allow tuple routing.

This doesn't allow routing tuple to the foreign partitions themselves,
but it permits tuples to be routed to regular partitions despite the
presence of foreign partitions in the same inheritance hierarchy.

Etsuro Fujita, reviewed by Amit Langote and by me.

Discussion: http://postgr.es/m/bc3db4c1-1693-3b8a-559f-33ad2b50b7ad@lab.ntt.co.jp

Branch
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REL_10_STABLE

Details
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https://git.postgresql.org/pg/commitdiff/08cb36417aa22436647a1831a7d1ff6b41232280

Modified Files
--------------
contrib/file_fdw/data/list1.csv | 2 +
contrib/file_fdw/data/list2.bad | 2 +
contrib/file_fdw/data/list2.csv | 2 +
contrib/file_fdw/input/file_fdw.source | 21 +++++++++
contrib/file_fdw/output/file_fdw.source | 81 +++++++++++++++++++++++++++++++++
src/backend/executor/execMain.c | 25 ++++++----
src/backend/executor/nodeModifyTable.c | 2 +-
src/include/executor/executor.h | 2 +-
8 files changed, 126 insertions(+), 11 deletions(-)