increase bin count for hash scan (#17562)

runtime/src/accounts_db.rs

@@ -4517,7 +4517,7 @@ impl AccountsDb {
         let mut scan_and_hash = move || {
             // When calculating hashes, it is helpful to break the pubkeys found into bins based on the pubkey value.
             // More bins means smaller vectors to sort, copy, etc.
-            const PUBKEY_BINS_FOR_CALCULATING_HASHES: usize = 64;
+            const PUBKEY_BINS_FOR_CALCULATING_HASHES: usize = 256;
 
             // # of passes should be a function of the total # of accounts that are active.
             // higher passes = slower total time, lower dynamic memory usage