pgsql: pg_{dump,restore}: Refactor handling of conflicting options.

pg_{dump,restore}: Refactor handling of conflicting options.

This commit makes use of the function added by commit b2898baaf7
for these applications' handling of conflicting options. It
doesn't fix any bugs, but it does trim several lines of code.

Author: Jian He <jian(dot)universality(at)gmail(dot)com>
Reviewed-by: Steven Niu <niushiji(at)gmail(dot)com>
Reviewed-by: Zsolt Parragi <zsolt(dot)parragi(at)percona(dot)com>
Discussion: https://postgr.es/m/CACJufxHDYn%2B3-2jR_kwYB0U7UrNP%2B0EPvAWzBBD5EfUzzr1uiw%40mail.gmail.com

Branch
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master

Details
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https://git.postgresql.org/pg/commitdiff/7c8280eeb5872f5c2663b562a9c6fcf8ec8a4b82

Modified Files
--------------
src/bin/pg_dump/pg_dump.c | 69 +++++++----------
src/bin/pg_dump/pg_dumpall.c | 2 +-
src/bin/pg_dump/pg_restore.c | 146 +++++++++++++-----------------------
src/bin/pg_dump/t/001_basic.pl | 26 +++----
src/bin/pg_dump/t/002_pg_dump.pl | 4 +-
src/bin/pg_dump/t/007_pg_dumpall.pl | 8 +-
6 files changed, 100 insertions(+), 155 deletions(-)