Remove old feature: simple_capitalization (#15763)

* Remove old feature: simple_capitalization

* Fix another failing test in core

* Finish up test cleanup

* Further clean up a bit

accounts-bench/src/main.rs

@@ -103,9 +103,7 @@ fn main() {
         } else {
             let mut pubkeys: Vec<Pubkey> = vec![];
             let mut time = Measure::start("hash");
-            let results = accounts
-                .accounts_db
-                .update_accounts_hash(0, &ancestors, true);
+            let results = accounts.accounts_db.update_accounts_hash(0, &ancestors);
             time.stop();
             let mut time_store = Measure::start("hash using store");
             let results_store = accounts.accounts_db.update_accounts_hash_with_index_option(
@@ -113,7 +111,6 @@ fn main() {
                 false,
                 solana_sdk::clock::Slot::default(),
                 &ancestors,
-                true,
                 None,
             );
             time_store.stop();