remove volatile qualifiers from pg_stat_statements

When Who What
2024-08-06 15:58:58 Nathan Bossart (bossartn) Closed in commitfest 2024-09 with status: Committed
2024-08-06 14:47:18 Nathan Bossart (bossartn) Added bossartn as committer
2024-08-06 14:47:16 Nathan Bossart (bossartn) New status: Ready for Committer
2024-07-30 18:48:32 Nathan Bossart (bossartn) Changed authors to Nathan Bossart (bossartn)
2024-07-30 18:48:32 Nathan Bossart (bossartn) Changed targetversion to 18
2024-07-30 18:48:27 Nathan Bossart (bossartn) Attached mail thread Zqkv9iK7MkNS0KaN@nathan
2024-07-30 18:48:27 Nathan Bossart (bossartn) Created patch record