pgsql: pg_dump: Reorganize dumpFunc() and dumpAgg()

pg_dump: Reorganize dumpFunc() and dumpAgg()

Similar to daa9fe8a5264a3f192efa5ddee8fb011ad9da365, instead of
repeating the almost same large query in each version branch, use one
query and add a few columns to the SELECT list depending on the
version.  This saves a lot of duplication.

Reviewed-by: Fabien COELHO <coelho@cri.ensmp.fr>
Discussion: https://www.postgresql.org/message-id/flat/6594334b-40fd-14f1-6bc5-877afa3feed5@2ndquadrant.com

Branch
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master

Details
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https://git.postgresql.org/pg/commitdiff/ed2c7f65bd9f15f8f7cd21ad61602f983b1e72e9

Modified Files
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src/bin/pg_dump/pg_dump.c | 496 +++++++++++++++-------------------------------
1 file changed, 159 insertions(+), 337 deletions(-)