pgsql: Fix inconsistency with HeapTuple freeing in extended_stats_funcs

Fix inconsistency with HeapTuple freeing in extended_stats_funcs.c

heap_freetuple() is a thin wrapper doing a pfree(), and the function
import_pg_statistic(), introduced by ba97bf9cb7b4, had the idea to call
directly pfree() rather than the "dedicated" heap tuple routine.

upsert_pg_statistic_ext_data already uses heap_freetuple(). This code
is harmless as-is, but let's be consistent across the board.

Reported-by: Yonghao Lee <yonghao_lee(at)qq(dot)com>
Discussion: https://postgr.es/m/tencent_CA1315EE8FB9C62F742C71E95FAD72214205@qq.com

Branch
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master

Details
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https://git.postgresql.org/pg/commitdiff/d5ea206728de7cb301d2f572055a76d4ea43bc8d

Modified Files
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src/backend/statistics/extended_stats_funcs.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)