Explicitly choose the setting of temp_store in better sqlite.

Memory isn't the default.

Co-authored-by: Bea <20361868+enbea@users.noreply.github.com>

src/backingstore/better-sqlite3/BetterSqliteStore.ts

@@ -24,7 +24,9 @@ export function makeBetterSqliteDB(
 ): Database {
   log.info("Opening db: ", options.path);
   const db = new BetterSqlite3(options.path, options);
-  if (options.path !== ":memory:") {
+  if (options.path === ":memory:") {
+    db.pragma("temp_store = memory");
+  } else {
     db.pragma("temp_store = file"); // Avoid unnecessary memory usage.
   }
   if (options.WALMode) {