add filler accounts to bloat validator and predict failure (#20491)

* add filler accounts to bloat validator and predict failure

* assert no accounts match filler

* cleanup magic numbers

* panic if can't load from snapshot with filler accounts specified

* some renames

* renames

* into_par_iter

* clean filler accts, too

core/src/accounts_hash_verifier.rs

@@ -134,6 +134,7 @@ impl AccountsHashVerifier {
                 HashStats::default(),
                 false,
                 None,
+                None, // this will fail with filler accounts
             )
             .unwrap();