pgsql: simplehash: Add support for resetting a hashtable's contents.

simplehash: Add support for resetting a hashtable's contents. A hashtable reset just reset the hashtable entries, but does not free memory. Author: Andres Freund Discussion: https://postgr.es/m/[email protected] Bug: #15592 #15486 Backpatch: 11, this is a prerequi

pgsql: simplehash: Add support for resetting a hashtable's contents.

simplehash: Add support for resetting a hashtable's contents. A hashtable reset just reset the hashtable entries, but does not free memory. Author: Andres Freund Discussion: https://postgr.es/m/[email protected] Bug: #15592 #15486 Backpatch: 11, this is a prerequi