pgsql: Fix memory leak in pg_restore with zstd-compressed data.

Fix memory leak in pg_restore with zstd-compressed data.

EndCompressorZstd() neglected to free everything.  This was
most visible with a lot of large objects in the dump.

Per report from Tomasz Szypowski.  Back-patch to v16
where this code came in.

Discussion: https://postgr.es/m/DU0PR04MB94193D038A128EF989F922D199042@DU0PR04MB9419.eurprd04.prod.outlook.com

Branch
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REL_16_STABLE

Details
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https://git.postgresql.org/pg/commitdiff/8cfff087b55f6688e2f3b5f1ba303dc5fb8222c6

Modified Files
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src/bin/pg_dump/compress_zstd.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)