Use standard tmp-snapshot- file prefix for the "new_state" archive for better cleanup/consistency

validator/src/bin/solana-test-validator.rs

@@ -220,6 +220,7 @@ fn main() {
             exit(1);
         })
     }
+    solana_runtime::snapshot_utils::remove_tmp_snapshot_archives(&ledger_path);
 
     let validator_log_symlink = ledger_path.join("validator.log");
     let logfile = if output != Output::Log {