pgsql: Refactor Copy{From|To}GetRoutine() to use pass-by-reference argu

Refactor Copy{From|To}GetRoutine() to use pass-by-reference argument.

The change improves efficiency by eliminating unnecessary copying of
CopyFormatOptions.

The coverity also complained about inefficiencies caused by
pass-by-value.

Oversight in 7717f6300 and 2e4127b6d.

Reported-by: Junwang Zhao <zhjwpku(at)gmail(dot)com>
Reported-by: Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> (per reports from coverity)
Author: Sutou Kouhei <kou(at)clear-code(dot)com>
Reviewed-by: Junwang Zhao <zhjwpku(at)gmail(dot)com>
Reviewed-by: Masahiko Sawada <sawada(dot)mshk(at)gmail(dot)com>
Discussion: https://postgr.es/m/CAEG8a3L6YCpPksTQMzjD_CvwDEhW3D_t=5md9BvvdOs5k+TA=Q@mail.gmail.com

Branch
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master

Details
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https://git.postgresql.org/pg/commitdiff/bacbc4863b3bfb79b9577f11f2c77e4df9f66d66

Modified Files
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src/backend/commands/copyfrom.c | 8 ++++----
src/backend/commands/copyto.c | 8 ++++----
2 files changed, 8 insertions(+), 8 deletions(-)