pgsql: Remove useless pstrdups in untransformRelOptions

Remove useless pstrdups in untransformRelOptions

The two strings are already a single palloc'd chunk, not freed; there's
no reason to allocate separate copies that have the same lifetime.

This code is only called in short-lived memory contexts (except in some
cases in TopTransactionContext, which is still short-lived enough not to
really matter), and typically only for short arrays, so the memory or
computation saved is likely negligible.  However, let's fix it to avoid
leaving a bad example of code to copy.  This is the only place I could
find where we're doing this with makeDefElem().

Reported-by: Junwang Zhao <zhjwpku@gmail.com>
Discussion: https://postgr.es/m/20220909142050.3vv2hjekppk265dd@alvherre.pgsql

Branch
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master

Details
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https://git.postgresql.org/pg/commitdiff/6710e83a675eda798544fea4cdcb89eef7f39403

Modified Files
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src/backend/access/common/reloptions.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)