pgsql: Prohibit identity columns on typed tables and partitions

Prohibit identity columns on typed tables and partitions

Those cases currently crash and supporting them is more work then
originally thought, so we'll just prohibit these scenarios for now.

Author: Michael Paquier <michael.paquier@gmail.com>
Reviewed-by: Amit Langote <Langote_Amit_f8@lab.ntt.co.jp>
Reported-by: Мансур Галиев <gomer94@yandex.ru>
Bug: #14866

Branch
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REL_10_STABLE

Details
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https://git.postgresql.org/pg/commitdiff/a2c6cf36608e10aa223fef49323b5feba344bfcf

Modified Files
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src/backend/parser/parse_utilcmd.c | 13 +++++++++++++
src/test/regress/expected/identity.out | 12 ++++++++++++
src/test/regress/sql/identity.sql | 16 ++++++++++++++++
3 files changed, 41 insertions(+)