Fix test_harness tests

They were broken by changes to TestingBeaconStateBuilder and where the
keypairs file is stored.

beacon_node/beacon_chain/test_harness/src/run_test.rs

@@ -1,6 +1,5 @@
 use crate::test_case::TestCase;
 use clap::ArgMatches;
-use std::path::Path;
 use std::{fs::File, io::prelude::*};
 use yaml_rust::YamlLoader;
 
@@ -17,10 +16,6 @@ pub fn run_test(matches: &ArgMatches) {
         };
 
         for doc in &docs {
-            let validators_dir = matches
-                .value_of("validators_dir")
-                .and_then(|dir_str| Some(Path::new(dir_str)));
-
             // For each `test_cases` YAML in the document, build a `TestCase`, execute it and
             // assert that the execution result matches the test_case description.
             //
@@ -35,7 +30,7 @@ pub fn run_test(matches: &ArgMatches) {
             // panics with a message.
             for test_case in doc["test_cases"].as_vec().unwrap() {
                 let test_case = TestCase::from_yaml(test_case);
-                test_case.assert_result_valid(test_case.execute(validators_dir))
+                test_case.assert_result_valid(test_case.execute())
             }
         }
     }