pgsql: pg_dump: Fix dumping of inherited generated columns

pg_dump: Fix dumping of inherited generated columns

Generation expressions of generated columns are always inherited, so
there is no need to set them separately in child tables, and there is
no syntax to do so either. The code previously used the code paths
for the handling of default values, for which different rules apply;
in particular it might want to set a default value explicitly for an
inherited column. This resulted in unrestorable dumps. For generated
columns, just skip them in inherited tables.

Reviewed-by: Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
Discussion: https://www.postgresql.org/message-id/flat/15830.1575468847%40sss.pgh.pa.us

Branch
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REL_13_STABLE

Details
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https://git.postgresql.org/pg/commitdiff/1d3ce0223c6a527c2f464fb8e6b3874be4e7332e

Modified Files
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src/bin/pg_dump/common.c | 31 +++++++++++++++++++++------
src/bin/pg_dump/pg_dump.c | 37 +++++++++++++++++++++++++++-----
src/bin/pg_dump/t/002_pg_dump.pl | 46 ++++++++++++++++++++++++++++++++++++++++
3 files changed, 102 insertions(+), 12 deletions(-)